Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a medium bowl, mix chopped shrimp, panko, mayonnaise, mustard, garlic, parsley, lemon zest, and paprika until combined.
Season the shrimp mixture with salt and pepper.
Lay salmon fillets flat and use a sharp knife to cut a horizontal pocket into the thickest part of each fillet, taking care not to cut through to the other side.
Divide the shrimp stuffing into four equal portions and pack into the salmon pockets.
Place the stuffed salmon fillets on the prepared baking sheet.
Brush the tops of the fillets with melted butter and season lightly with salt and pepper.
Bake for 18 to 20 minutes until the salmon flakes easily with a fork and the shrimp filling is opaque and cooked through.
Serve immediately with fresh lemon wedges.