Heat oil in large skillet. Add the yellow and red onions and saute over moderate heat 5 min. Stir in wine, add leeks. Saute another 15 min, stir frequently, or until onions are golden and leeks are limp. Remove from heat.
Preheat oven 350F. In mixing bowl, combine beaten eggs with two tablespoons of the parsley, dill, tarragon, feta cheese, and pepper. Stir in the onion mixture.
Oil a 10 in. tart pan and line bottom generously with bread crumbs. Pour in onion mixture. Ring the outside edge with tomato slice, then sprinkle the remaining parsley in the center. Sprinkle a light layer of bread crumbs over the entire top. Bake for 40 to 45 min, or until the mixture is set and top is golden. Let stand for 5 to 10 min, then cut into wedges.