Cut tomatoes into wedges, and seed. Cut cucumber into thin slices; cut bell pepper into thin strips. Cut onion into slices, and separate into rings.
Drain artichoke hearts, reserving 1/4 cup marinade.
Whisk together reserved artichoke marinade, next 5 ingredients, and, if desired, sugar in a large bowl. Add cut vegetables, artichokes, lettuce, and olives, tossing to coat. Cover and chill at least 30 minutes. Sprinkle with feta cheese just before serving. Serve with pita wedges, if desired.