Prep the shrimp. Pat your shrimp dry with paper towels and season with smoked paprika, cayenne, salt, and pepper.
Cook the garlic butter shrimp. Melt 3 tablespoons of butter in a large skillet over medium-high heat. Add the minced garlic and sauté for about 30 seconds until fragrant. Add the shrimp in a single layer and cook for 1–2 minutes per side until pink and cooked through. Remove from heat, squeeze lime juice over top, and toss with cilantro. Set aside.
Assemble the quesadillas. Lay a tortilla flat and sprinkle half with about 1/2 cup of shredded cheese. Add a few shrimp and some roasted red pepper slices, then top with another small handful of cheese. Fold the tortilla in half.
Cook the quesadillas. Heat a little butter or oil in a skillet or griddle over medium heat. Cook each quesadilla for 2–3 minutes per side until golden brown and the cheese has melted. Repeat with remaining tortillas.
Slice and serve. Cut each quesadilla into 3 wedges and serve immediately with your favorite toppings.