Preheat oven to 425°. In a large skillet, cook beef over medium heat, 6-8 minutes or until no longer pink, crumble meat; drain. Stir in taco seasoning and 1 can of undrained tomatoes; heat through., Mix beans, 1/2 cup cheese, cilantro, remaining can of undrained tomatoes and, if desired, pepper sauce. Spread onto bottom of a greased 13x9-in. baking dish., Stand taco shells upright on bean mixture. Fill each with 1 tablespoon cheese and about 1/3 cup beef mixture. Bake, covered, 15 minutes., Uncover; sprinkle with remaining cheese. Bake, uncovered, 5-7 minutes or until cheese is melted and shells are lightly browned. Sprinkle with green onions.