In a large skillet, cook the beef, onion, green pepper and garlic over medium heat until meat is no longer pink; drain. Add tomato paste, water and seasonings; cook over low heat until thickened, about 10 minutes.
Spread 1 tablespoonful on each slice of bread. Place on ungreased baking sheets; sprinkle with cheese. Bake at 350° for 8-10 minutes or until heated through.