Easy Mexican Tostada

Name: Easy Mexican Tostada
Prep time: 15 min
Cook time: 10 min
Total time: 25 min
Cuisine: Mexican
Ingredients: 10 tostada shells ((or regular corn tortillas, if making your own tostada shell)); 1 can Refried Beans; 1 lb ground beef (,( or substitute cooked shredded chicken, pork or beef)); 1/4 onion (, diced); 1 Tablespoon chili powder; 1 1/2 teaspoons cumin; 1/2 teaspoon EACH paprika and salt; ¼ teaspoon EACH garlic powder, oregano, black pepper; 1/2 head lettuce (, finely chopped); queso fresco ((or other cheese)); 1 large avocado; Mexican crema ((or sour cream)); Salsa (, pico de gallo or salsa verde)