Crumble the sausage into a saucepan over low heat; cover and cook until sausage is completely browned, stirring every 30 seconds; drain.
Place the bread on a baking sheet with the crust sides down. Arrange the cooked sausage evenly over both halves of bread. Top each with tomato slices, red bell pepper strips, mozzarella slices, green olives, and black olives.
Bake in preheated oven for 10 minutes.
Whisk together the olive oil, balsamic vinegar, oregano, basil, salt, pepper, onion, and garlic in a bowl. Drizzle over baked bread halves.
Bake another 5 minutes. Cut into 2 inch slices to serve.
