In a pan, add 2 tablespoons oil. Add beef, breaking up with a wooden spoon, season with salt and pepper, sauté with garlic and onion until softened about 3 to 4 minutes on medium heat.
Add taco seasoning, tomato paste, 1 tbsp water and black beans; cook on medium-low for 5 minutes. Turn off heat and mix in avocado and cilantro.
Preheat another a large non-stick pan over medium heat with 2 teaspoon oil. Place a tortilla in the pan and sprinkle half with cheese, beef mixture. Fold tortilla over and fry lightly on both sides until cheese is melted. Repeat with remaining tortillas.
Cut quesadillas half and serve with lime wedges and sour cream. Enjoy!
Recipe by Mom's Mexican Recipes at https://www.moms-mexican-recipes.com/beef-quesadillas-recipe