01 - Combine tomatoes, red onion, jalapeño, cilantro, lime juice, salt, and pepper in a mixing bowl. Toss thoroughly and refrigerate until serving.
02 - Halve avocados, remove pits, and scoop flesh into a bowl. Mash with fork to desired consistency. Add tomato, red onion, cilantro, lime juice, salt, and pepper. Mix until incorporated and set aside.
03 - Heat olive oil in large skillet over medium heat. Sauté onion until translucent, approximately 2 minutes. Add garlic and cook 30 seconds. Add ground beef, breaking apart with spoon, and cook until browned, 5-7 minutes. Drain excess fat if necessary.
04 - Stir in bell pepper, cumin, smoked paprika, chili powder, salt, and black pepper. Continue cooking 3-4 minutes until peppers have softened. Remove from heat.
05 - Arrange tortillas on flat surface. Distribute half the cheeses evenly across four tortillas. Layer seasoned beef mixture over cheese, then top with remaining cheese. Place remaining tortillas on top to form sandwiches.
06 - Heat large skillet or griddle to medium. Cook each quesadilla 2-3 minutes per side until tortilla is golden brown and cheese has melted completely. Let rest 1 minute before cutting into wedges.
07 - Arrange quesadilla wedges on serving plates. Accompany with prepared salsa and guacamole on the side. Serve immediately while hot.