How to Make It
Combine pineapple, cilantro, red onion, lime juice, and salt in a medium bowl. Toss pork with 1/2 cup pineapple mixture. Add avocado and bell pepper to remaining pineapple mixture; set aside.
Sprinkle 1/4 cup cheese over each of 4 tortillas; top evenly with pork mixture. Sprinkle evenly with remaining cheese, and top with remaining tortillas.
Heat 2 tablespoons of the butter in a large nonstick skillet over medium-high. Add 1 quesadilla to skillet, and cook until tortillas are golden brown and cheese is melted, about 2 minutes per side. Repeat with remaining butter and quesadillas. Cut quesadillas in half, and serve with remaining pineapple relish and lime wedges.