Preheat oven to 425 degrees F.
Cook ground beef, breaking it apart while cooking. Drain grease from meat when beef is browned. Add onion, salt, chili powder, cumin, garlic, red pepper, and oregano and stir well. Remove from heat.
For flower/star cups: Knead pie dough until no longer crumbly. Roll out on plastic wrap and cut into 12 squares approximately 4 1/2 inches. Tuck squares into every other muffin tin allowing points to stick out on tin. Press any dough flaps in muffin tin to create more room for filling and to make a neater appearance (see photo).
For plain taco cups: Knead pie dough until no longer crumbly. Roll dough into a snake or rope. Cut into 16 equal pieces. Place a piece of dough into a muffin tin, pressing into an even layer on bottom and sides of muffin tin.
Divide meat between pastry cups. Bake in preheated 425 degree F oven 15 to 18 minutes or until pie crust is golden brown and cooked through.
Remove taco cups from pie tin and top with your favorite taco fixings, like guacamole, salsa, olives or fresh cilantro.