Preheat oven to 375°. In a large skillet, cook beef and onion over medium heat 6-8 minutes or until beef is no longer pink, breaking meat into crumbles; drain. Stir in taco seasoning and refried beans; heat through., Unroll each tube of dough into a long rectangle. Cut each rectangle into 12 pieces; press lightly onto bottoms and up sides of 24 ungreased muffin cups. , Fill each muffin cup with a rounded tablespoon of beef mixture; sprinkle each with 1 tablespoon cheese. Bake 14-16 minutes or until dough is golden brown. Cool taco cups in pans 10 minutes before removing. Serve with toppings as desired.