Bake or Fry the corn tortillas, if not using store bought tostada shells.
Add ground beef to a skillet over medium heat. Cook, breaking into small pieces with a wooden spoon, until browned. Remove grease.
Add onion and seasonings and cook an additional few minutes.
Add the refried beans to a microwave safe bowl, or a small skillet over medium heat. Stir in a small scoop of sour cream. Cook until warmed through.
Assemble the tostadas: Spread a thin layer of refried beans over the tostada shell. Top with a small spoonful of ground beef, then lettuce, cheese, avocado, salsa, sour cream and hot sauce.
Serve immediately.
Video
Notes
To make ahead: Have everything prepped and stored separately in the fridge. When ready to eat, re-warm the meat and beans and assemble the tostadas.