Cucumber Tomato and Onion Salad
This Cucumber Tomato and Onion Salad is crisp, tangy, and endlessly refreshing. Tossed in a 2-to-1 vinegar and olive oil dressing, it comes together in minutes and gets better as it sits. Make it ahead, keep it in the refrigerator all week, and serve it alongside anything off the grill.
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If summer were defined by a salad, this would be it.
My mom always had some variation of a cucumber tomato and onion salad marinating in the refrigerator from about May until it was time to put up the Halloween decorations. It was almost always made with vegetables from our own garden. We grew a rather large one throughout my childhood and even had a separate piece of land for our not-so-humble crop going into my teenage years.
That garden produced an abundance of cucumbers and tomatoes every year, and there were always onions around to complete the trio. This was, without question, my mom’s favorite salad. Her version lived in mammoth-sized Tupperware bowls in the refrigerator, and the bowl was never empty for long. As a recipe developer who has been cooking from the garden my entire life, this is the recipe I come back to every summer without fail.
This version mimics what she would make, a vinegar-forward dressing with a 2-to-1 ratio of vinegar to oil that gives the whole thing an almost quick pickle quality. You can eat it immediately, but it gets better after a few hours in the refrigerator when the vegetables have had time to absorb the dressing. I often pair it with hard-boiled eggs or canned tuna for a quick, healthy lunch that doesn’t feel like a compromise.
If you love this combination of flavors, my Greek Cucumber and Tomato Salad takes the same foundation in a completely different direction with feta cheese, olives, and a more herb-forward dressing.
Choosing Your Vegetables
The beauty of this salad is that the three core ingredients: cucumber, tomato, and onion. They’re all flexible, in terms of the style and size you choose. Here is how I think about each one.
- Cucumber: The recipe calls for one English cucumber, which has thin skin, fewer seeds, and a mild flavor that works beautifully in a vinegar dressing. Persian cucumbers, pickling cucumbers, or a standard American slicing cucumber all work well as substitutes. If you’re using a thicker-skinned cucumber, peel it first.
- Tomato: I prefer a pint of cherry or grape tomatoes, which is what still grows best in my own garden. They tend to be sweeter and hold their shape well in the dressing. Plum or beefsteak tomatoes work equally well, just cut them into consistent pieces so everything marinates evenly.
- Onion: Red onion is my preference for the color it adds to the bowl, but yellow or white onion works just as well. If raw onion is too sharp for your taste, soak the sliced onion in cold water for 10 minutes before adding it to the salad to take the edge off without losing the flavor.
The Dressing
The dressing is what makes this salad what it is. The 2-to-1 ratio of vinegar to olive oil is intentional and gives the whole thing a slightly pickled quality that keeps the vegetables tasting bright even after a few days in the refrigerator.
Red wine vinegar is the default and is a natural pairing with oregano, but this is a recipe that rewards flexibility. Apple cider vinegar adds a subtle sweetness. White balsamic brings a milder, slightly fruity note that I especially love when tomatoes aren’t in peak season. I often go half-and-half with two different vinegars to add complexity. Use whatever you have on hand, as the ratio matters more than the variety.
Tips for Making it ahead
This salad is at its best after at least 30 minutes in the refrigerator, and genuinely improves over 24 hours as the vegetables soften slightly and absorb the dressing. A few things worth knowing:
- Fresh herbs don’t hold up as well as dried. Dried oregano, dill, or whatever is calling out to you from the spice drawer will hold up well for several days in the dressing. Fresh herbs are a nice finishing touch but will wilt and discolor if left in the salad for too long.
- The cucumber releases water as it sits. This is normal and actually contributes to the marinade. If the dressing seems thin after a day, give it a stir and taste for seasoning. A small splash of vinegar usually wakes it up.
- Store it in a large airtight container. My mom used her biggest Tupperware bowl, which is still the right call. The vegetables need room to marinate evenly, and a wide container makes it easier to serve directly from the refrigerator all week.
Serving Suggestions
This salad works alongside almost anything, including grilled shrimp skewers, burgers, or as part of a quick cold plate lunch with hard-boiled eggs and canned tuna. It’s also a natural companion to anything else coming off the grill in the summer months. The vinegar-forward dressing cuts through richer foods particularly well, which makes it a useful counterpoint on a summer table.
The best part of this memory-evoking salad is that you can eat it until you find the bottom of the bowl and remain free of guilt. It’s just that simple and deliciously satisfying.
If you make this, leave a star rating and let me know in the comments what vinegar you used or what vegetables you swapped in. I love seeing how people make this one their own.
Cucumber Tomato and Onion Salad
Ingredients
- 1 English cucumber, sliced or cut into half-moons
- 1 pint cherry or grape tomatoes, halved
- ½ small red onion, thinly sliced
- ⅔ cup red wine vinegar
- ⅓ cup olive oil
- 1 teaspoon dried oregano
- ½ teaspoon kosher salt
- ¼ teaspoon black pepper
Instructions
- Make the dressing by whisking together the red wine vinegar, olive oil, dried oregano, salt, and pepper in a small bowl or jar until combined.
- Add the cucumber, tomatoes, and red onion to a large bowl. Pour the dressing over the vegetables and toss to coat evenly.
- Serve immediately or cover and refrigerate for at least 30 minutes before serving. The salad improves with time and keeps well for up to 5 days in the refrigerator.
Notes
- Cucumber swaps: Persian, pickling, or American slicing cucumbers all work. Peel thicker-skinned varieties before slicing.
- Tomato swaps: Plum or beefsteak tomatoes work well. Cut into consistent pieces for even marinating.
- Onion tip: Soak sliced red onion in cold water for 10 minutes to mellow the sharpness before adding to the salad.
- Vinegar flexibility: Apple cider vinegar or white balsamic work beautifully in place of red wine vinegar, or go half-and-half for added complexity.
- Herbs: Dried oregano or dill hold up well for several days. Add fresh herbs as a finishing touch just before serving rather than mixing them in ahead of time.
- Make ahead: This salad gets better after 24 hours in the refrigerator as the vegetables absorb the dressing. Stir and taste before serving, adding a small splash of vinegar to refresh, if needed.
- Serving suggestion: Pair with hard-boiled eggs or canned tuna for a quick, complete lunch straight from the refrigerator.
- Greek variation: Try my Greek Cucumber and Tomato Salad for a feta and olive version built on the same foundation.
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