Preheat oven to 450°.
Place bread in a food processor; pulse until crumbly. Place the trout, skin side down, on a jelly roll pan coated with cooking spray. Combine mustard and tarragon; spread over top of fish. Sprinkle fish with breadcrumbs and paprika; lightly coat with cooking spray. Bake at 450° for 10 minutes or until fish flakes easily when tested with a fork. Serve with lemon wedges.