01 - Combine diced tomatoes, red onion, jalapeño, cilantro, lime juice, salt, and pepper in a bowl. Mix thoroughly, cover, and refrigerate until serving time.
02 - Halve and pit avocados, then scoop flesh into a bowl. Mash with a fork to desired consistency. Stir in tomato, onion, lime juice, cilantro, salt, and pepper. Press plastic wrap directly onto surface and refrigerate.
03 - Heat olive oil in a large skillet over medium heat. Add onions and cook for 2–3 minutes until softened. Add garlic and bell pepper; cook for another 2 minutes. Add ground beef, breaking apart with a spoon, and cook until browned and cooked through, approximately 5–7 minutes. Drain excess fat if necessary.
04 - Add cumin, smoked paprika, chili powder, oregano, salt, and black pepper to the beef mixture. Stir until well combined and spices are evenly distributed. Remove from heat.
05 - Lay out tortillas on a clean surface. Sprinkle half of each tortilla with an even layer of cheddar and Monterey Jack cheese blend. Top with a generous portion of the seasoned beef mixture, then add another light layer of cheese. Fold tortillas in half to fully enclose the filling.
06 - Wipe out the skillet and return to medium heat. Cook each quesadilla for 2–3 minutes per side, pressing gently with a spatula, until golden brown and cheese is completely melted. Transfer to a cutting board and cut into wedges.
07 - Serve quesadillas warm, accompanied with fresh salsa, guacamole, sour cream if desired, and lime wedges on the side.