To prepare sauce: In deep nonstick 12-inch skillet, cook sausage over medium-high heat, stirring occasionally, until browned on all sides, about 5 minutes.
Reduce heat to medium. Discard all but 2 tablespoons sausage drippings from skillet. Add garlic, peppers and onion to sausage and cook, covered, until vegetable are tender, about 10 minutes, stirring occasionally.
Stir in tomatoes with their purée, tomato purée and salt; heat to boiling over medium heat, breaking up tomatoes with side of spoon. Reduce heat to low; cover and simmer 10 minutes.
Meanwhile, preheat oven to 400 degrees. In large saucepot, cook pasta 2 minutes less than directed on label. Drain pasta; return to saucepot. Add sauce and stir until pasta is evenly coated. Add mozzarella; toss to combine.
Transfer pasta mixture to 9- by 13-inch baking dish and spread evenly; sprinkle with Romano cheese. Bake, uncovered, until hot and bubbling and top is brown, 20 to 25 minutes. Let stand 10 minutes for easier serving.