Chop cucumber in pieces less than 1/2 inch and put in colander.: The cucumber should be diced small so it blends with the other elements, providing a crisp, cool counterpoint. As you chop, you'll hear a clean, watery snap as the knife hits firm flesh, and the pale green cubes should glisten. Placing them in a colander helps excess water drain away, preventing a soggy salad. A common mistake is cutting unevenly, which leads to inconsistent texture. If your pieces are too large the salad becomes uneven, so aim for uniformity.
Add a generous amount of salt and let sit while you chop other ingredients.: Salting the cucumber draws out excess moisture and concentrates flavor, creating a firmer bite. You may notice tiny beads of liquid pooling in the colander after a few minutes; that is the salt doing its work. This step also seasons from within, so you need less finishing salt. Avoid over salting early on, or the salad can become too saline; if you do oversalt, briefly rinse and drain the cucumber.
Chop tomatoes in same-size pieces as the cucumbers. If the tomatoes are juicy I sometimes put them in a colander and let the juice run out.: Matching the tomato dice to the cucumber ensures every forkful combines textures. When you cut into ripe tomatoes you'll see seeds and juice; letting them drain reduces liquid in the bowl and keeps the dressing from thinning. The sound is quieter than cucumber, more of a soft thud when your knife hits the flesh. A typical error is using overripe tomatoes that mush apart, so choose tomatoes that are ripe yet structurally sound.
Chop onions (Cucumbers, tomatoes, and onions should be cut in same-size pieces.): Finely dicing the onion gives sharpness without dominating. As you chop you may notice a sulfurous scent that will mellow once mixed and lightly salted. Uniform pieces help the onion integrate, giving balanced pops of sharpness. Avoid large chunks that can overpower; if raw onion seems too pungent, brief cold water soak can tame it.
Parsley and mint should be chopped very finely.: The herbs are aromatic powerhouses, so chopping them finely releases essential oils and ensures they distribute evenly. You'll smell a bright, herbaceous fragrance as you work, and finely cut leaves create a green, feathery texture. Large leaves can be chewy and create uneven herb pockets, so take the extra minute to mince them. Keep herbs cold and dry to avoid bruising and losing volatile aromas.
When all ingredients are chopped, combine in mixing bowl.: At this point the colors come alive in the bowl, with bright red tomato , pale green cucumber , and flecks of green herbs. Combining them allows flavors to begin marrying even before dressing is added. Use a large bowl so you can gently toss without bruising the herbs. A common slip is overcrowding the bowl which can crush delicate leaves, so use space and gentle hands.
Mix in olive oil, lemon juice, salt and pepper.: Adding olive oil and lemon juice at this stage coats the vegetables and brings harmony. As you toss the salad you'll notice a glossy sheen and a citrusy brightness lifting the herbs and vegetables. Grind fresh black pepper and add salt incrementally, tasting as you go. The biggest mistake is adding too much acid at once; balance with oil and adjust seasoning slowly.
Serve immediately.: This salad shines when fresh, with crisp textures and bright aromatics. Serve right away to preserve the herb fragrance and cucumber crunch. If you must wait, chill briefly but know the herbs will soften over time and the salad will become more melded. Do not leave it too long or it will lose its lively character; short resting is okay, extended sitting flattens the flavors.