Brown the ground beef in a large skillet over medium-high heat with the chopped onion. Drain excess grease.
Season the beef mixture with salt, pepper, chili powder, cumin, dried cilantro, cayenne pepper, and minced garlic. Stir well.
Lightly fry each flour tortilla in vegetable oil until golden brown. Place on paper towels to absorb excess oil.
Spread warmed refried beans over each fried tortilla, add the ground beef mixture, sprinkle cheese, and top with another tortilla. Drizzle taco sauce and add more cheese.
Preheat oven to 400°F (200°C) and bake the assembled pizzas for about 10 minutes until heated through and bubbly. Top with diced tomatoes and green onions.