Remove sausage from casings and saute sausage in 2 tablespoons olive oil until browned. Drain to remove excess oil. Remove from skillet and set aside. In skillet, heat 3 tablespoons olive oil, add onions, garlic and saute stirring until onions wilt down. Add tomato sauce, salt, pepper and red pepper to taste. Simmer about 5 minutes on low.
Stir together the sausage and onion and chopped olives. Toast bread lightly under broiler. Top with sausage mix and sprinkle grated mozzarella over all. Broil about 3 minutes under broiler until cheese melts. Watch carefully with oven door open. Remove from broiler, slice and serve.