Preheat oven to 350 degrees F (175 degrees C). Place peppers in a greased baking dish; set aside. Place crumbled bread in a large bowl, and sprinkle with 1/2 cup water; set aside.
Heat oil in a large heavy skillet over low heat. Saute onion until translucent, then stir in garlic. Let garlic cook for 2 minutes, then stir into bread. Add anchovies, olives, olive oil, black pepper and red pepper. Mix until well blended. Mound pepper halves with stuffing. Surround peppers with tomato sauce and a small amount of water. Cover with foil.
Bake in preheated oven for 45 to 60 minutes, or until peppers are tender. Uncover for the last 15 minutes of baking, and baste occasionally with sauce.