Core and seed the tomatoes if very seedy. Cut tomatoes into approximately 1/2-inch dice so pieces are small and uniform. Place diced tomatoes into a large mixing bowl.

Prepare cucumber

If using English or Persian cucumber, peel if desired and cut lengthwise if large. Remove any large seeds with the tip of a spoon if watery. Chop into 1/2-inch dice and add to the bowl with tomatoes.

Slice onion

Trim and halve the red onion. Slice thinly, then chop into small pieces (about 1/8–1/4 inch) so they are well distributed. Add to the bowl. If onion is very sharp, soak chopped pieces in cold water for 5 minutes then drain to mellow the flavor.

Chop parsley

Rinse and dry parsley. Remove large stems and finely chop the leaves. Add parsley to the bowl.

Add feta

Crumble the feta cheese and reserve until after tossing (you can save a small amount for topping).

Dressing

In a small bowl or jar, combine the red wine vinegar, lemon juice, Dijon mustard, and honey (if using). Whisk or shake to combine until mustard is emulsified.

Slowly whisk in the olive oil in a steady stream (or add to jar and shake vigorously) until the dressing is fully combined and slightly thickened.

Season dressing with salt and freshly ground black pepper. Taste and adjust: add a little more honey for sweetness, more vinegar for acidity, or a pinch more salt as needed.

Assemble & Serve

Pour the dressing over the chopped vegetables in the large bowl. Using two large spoons or salad hands, gently toss until the vegetables are evenly coated with dressing. Toss just enough to combine; do not mash the tomatoes.

Fold in about half of the crumbled feta so some is integrated into the salad and some remains for topping.

Transfer salad to a serving bowl or platter. Sprinkle the remaining feta on top and grind a little extra black pepper if desired.

Let the salad rest for 5–10 minutes at room temperature to allow flavors to meld, then serve. If not serving immediately, refrigerate for up to 2 hours; toss again gently before serving.