Prepare pasta according to package directions; drain and set aside.
Heat the oil in a large nonstick skillet. Add the onion and bell pepper and cook until slightly softened, 2 to 3 minutes. Add water and continue cooking, stirring occasionally, until the vegetables are tender, about 8 minutes. Add the sausage and cook, breaking up with back of a wooden spoon, until browned, 6 to 8 minutes. Stir in the tomatoes and seasonings; bring to a boil. Reduce the heat and simmer, covered, until the flavors are blended, about 15 minutes.
Preheat the oven to 375Â°F. Spray a 1-1/2-quart casserole with nonstick spray.
Add the cooked pasta to the skillet, tossing well to combine. Spoon half the pasta mixture into the casserole. Sprinkle with 1/2 of cheese. Spoon the remaining pasta mixture over top. Sprinkle with the remaining cheese. Cover loosely with a tent of foil sprayed with nonstick spray. (Do not let foil touch cheese). Bake until the filling is hot and bubbly and the cheese is melted, 20 to 25 minutes. Let stand 5 minutes before serving.