1. In a large skillet, cook beef and onion until meat is browned, about 10 minutes; drain off fat. Stir in undrained stewed tomatoes, tomato sauce, chili peppers, chili powder and cumin; bring to a boil. Add salt and pepper to taste.
2. Stir in uncooked macaroni and kidney beans. Return to a boil, reduce heat, cover and simmer until macaroni is tender, about 15 minutes.
3. To serve, spoon into bowls and sprinkle with grated cheese.