Marinated Cucumber, Tomato & Onion Salad

Fresh, simple, and full of flavor, this Marinated Cucumber, Tomato & Onion Salad is a classic side dish that never goes out of style. Combining crisp cucumbers, juicy tomatoes, and thinly sliced onions with a tangy homemade dressing, this salad is light, refreshing, and incredibly easy to prepare.

It’s the perfect addition to summer barbecues, family dinners, picnics, or any meal that needs a burst of freshness.

Ingredients

The Fresh Produce Base

Cucumbers: 2 large, thinly sliced into uniform rounds (peel if desired)
Tomatoes: 3 medium, chopped into bite-sized pieces (or 1½ cups halved cherry tomatoes)
Yellow or red onion: 1 medium, thinly sliced into half-moons

The Tangy Emulsified Dressing

Vinegar: ½ cup (apple cider or white distilled vinegar)
Olive oil or vegetable oil: ¼ cup
Water: ¼ cup
Granulated sugar: 2 tablespoons
Fine sea salt: 1 teaspoon
Black pepper: ½ teaspoon

The Food Science of Acid Marinating & Texture

Osmotic Dressing Absorption: Combining vinegar, sugar, and salt creates a high-tonicity liquid environment. When poured over raw vegetables, the dressing draws out a fraction of the cucumbers’ internal moisture while replacing it with tangy, sweet flavor compounds.
Cell-Wall Softening over Time: Unlike leafy greens that wilt rapidly, dense vegetables like cucumbers and onions retain their core crunch while their outer layers absorb the marinade. The salad hits its flavor peak after 2 to 24 hours of cold marination.
Emulsified Lipid Barrier: Incorporating ¼ cup of oil creates a light barrier around the tomato pieces, protecting their structural integrity and slowing down excess breakdown during prolonged refrigeration.