In a pan, heat vegetable oil over medium-high heat. Cook onion and garlic until fragrant, about 3 minutes, then add ground beef.
Stir until the ground beef turned slightly brown then add tomato paste, cumin powder, salsa & guacamole, salt, and black pepper. Stir until combined and cooked. Once cooked, transfer the beef to a bowl.
Place tortilla on work surface. Add half of the tortilla sides with mozzarella cheese, cheddar cheese, beef, then cheddar cheese, and mozzarella cheese again sequentially. Fold in half.
Heat 2 tsp vegetable oil over medium-low heat. Cook cheese beef quesadilla for about 3 minutes until browned and crispy. Carefully flip it and cook for another 3 minutes.
Transfer to a cutting board and cut it in half. Serve immediately, enjoy!