MAKE THE BEEF SAUCE
In a skillet, sauté the onion and garlic in vegetable oil.
Add the ground beef and bell peppers, and cook until browned.

Add the paprika, red pepper flakes, salt, oregano, and chopped cilantro. Mix well and cook for 1 minute.
Stir in the tomato sauce, heat through, and set aside to cool.

MAKE THE QUESADILLAS
In a bowl, mix the mozzarella and cheddar cheeses together.
Lay the tortillas on the counter and cover the bottom half of each tortilla with the cheese mixture.
Spoon the beef sauce over the cheese. Sprinkle the remaining cheese on top of the beef sauce.

Fold the tortillas in half to form a half-moon shape.
Heat a skillet with a little oil and brown 2 quesadillas at a time.

On a cutting board, cut each quesadilla into 3 triangles.
Serve immediately on a plate with small bowls of mashed avocado, pico de gallo, and sour cream.