In a small microwave-safe dish, combine green pepper and butter. Microwave, uncovered, on high for 1-2 minutes or until crisp-tender. Stir in the bread, cheese, mayonnaise and mustard.
Sprinkle fillets with salt and pepper; spread with bread mixture. Carefully roll up. Place seam side down in a shallow microwave-safe dish coated with cooking spray. Sprinkle with paprika. Cover and microwave on high for 3-5 minutes or until fish flakes easily with a fork.