Wash the vegetables thoroughly and drain them. The secret to a great Greek salad is using the freshest, in-season ingredients: ripe, flavorful tomatoes; firm, crisp cucumbers without seeds; fragrant, fresh bell peppers; and slightly spicy red onions. Slice the onion. Leave some slices whole and separate others into thin strips.

Remove the seeds and white membranes from the bell pepper. Slice it, then cut into thin strips. Wash the cucumber well, since you'll slice it (optionally with the skin) into thin rounds. Slice the tomatoes as well. Collect any tomato juices that run out while cutting and set them aside in a bowl—these are essential for the salad.

In a bowl, add 1 tablespoon of the olive oil and the collected tomato juices. Mix well. This blend of Greek olive oil and juicy tomato, along with the feta you'll add later, is what makes this salad unbeatable. Squeeze the extra juicy tomato into the bowl to extract all its juices (do not add the flesh to the salad).

Add the purslane, capers, and caper leaves (if using).

Cut the feta into thin but wide slices and place them on top of the salad. Add the olives for extra flavor and a pop of color.