Wash and dry the tomatoes, cucumber, and green pepper. Clean off the outer skin from the onion, wash, and dry.
Cut the tomatoes into bite-sized irregularly shaped chunks, removing the core. Slice the cucumber into 1/4-inch slices, cutting slices in half (whether or not you peel the cucumber is a personal choice). Slice the pepper into rings, removing the stem and seeds. Slice the onion into thin rings.
Combine the tomatoes, cucumbers, green pepper and onion in a large salad bowl. Sprinkle with oregano, Salt, black Pepper, pour olive oil over the salad, and toss. Just before serving, place the feta on top of the salad, either as a slice or crumbled (as in photo), and toss in some olives. Now mix everything together and enjoy.