In a mixing bowl, toss the shrimp with lime juice, chili powder, ground cumin, salt, and black pepper. Set aside to marinate for 5 minutes.

Heat 1 tablespoon olive oil in a skillet over medium-high heat. Add marinated shrimp and cook for 2-3 minutes per side, until just cooked through and pink. Remove shrimp to a plate and chop into bite-sized pieces.

Add remaining 1 tablespoon olive oil to the same skillet. Add diced red bell pepper and red onion. Sauté for 3-4 minutes until soft. Add minced garlic and cook for 30 seconds more. Return the chopped shrimp to the pan, toss everything together, and turn off the heat. Stir in chopped cilantro.

Lay out the tortillas. On one half of each tortilla, sprinkle about ¼ of the cheese, then spread ¼ of the shrimp and vegetable mixture over the cheese. Top with remaining cheese. Fold tortilla in half to enclose filling.

Heat a clean skillet over medium heat. Place a folded quesadilla in the pan. Cook for 2-3 minutes per side, pressing gently with a spatula, until tortillas are golden and crisp and cheese is melted. Repeat with remaining quesadillas.

Cut quesadillas into wedges. Serve hot, with sour cream, salsa, or guacamole on the side if desired.