Make the Tostada Shells:
Preheat oven to 400°F or heat oil in a skillet over medium heat. For baking, lightly brush both sides of the tortillas with oil and bake for 5–7 minutes per side until crispy. For frying, cook each tortilla for about 30–60 seconds per side until golden and crisp. Drain on paper towels.

Prepare the Ground Beef:
In a skillet, heat olive oil over medium heat. Add chopped onion and sauté until soft, about 3 minutes. Stir in garlic and cook for 1 more minute.

Add ground beef, breaking it up with a spoon. Cook until browned and fully cooked, about 7–10 minutes. Drain any excess fat.

Stir in chili powder, cumin, paprika, oregano, salt, pepper, and tomato sauce. Let simmer for 5 minutes. Remove from heat.

Assemble the Tostadas:
Spread a layer of warm refried beans on each crispy tostada shell. Top with a spoonful of seasoned beef, followed by lettuce, tomatoes, cheese, avocado, and any additional toppings you like.

Add a dollop of sour cream, sprinkle with chopped cilantro, and drizzle with hot sauce or salsa if desired.

Serve immediately and enjoy!