Wash cucumbers and tomatoes under cool running water. Slice cucumbers into thin rounds or half-moons.

Chop tomatoes into bite-sized pieces. If using red onion, thinly slice and soak in cold water for 5-10 minutes to mellow flavor, then drain.

In a large mixing bowl, combine all prepped vegetables: cucumbers, tomatoes, and drained onions. Toss gently.

In a separate bowl, whisk together olive oil and your choice of vinegar or lemon juice. Add salt and pepper to taste. If using garlic, incorporate it now.

Pour dressing over the combined vegetables. Gently toss to coat without crushing tomatoes.

Sprinkle in freshly chopped parsley or other herbs. Fold them into the salad.

Let salad sit for 10-15 minutes before serving to meld flavors, or serve immediately if in a hurry.