Thaw fish, if frozen. Rinse fish; pat dry. Place fish, skin side down, in a shallow dish. In a small bowl stir together sugar, 1-1/2 teaspoons of the orange peel, salt, and pepper. Sprinkle mixture evenly over fish (not on skin side); rub in with your fingers. Cover and marinate in the refrigerator for 8 to 24 hours.
Meanwhile, for salsa, in a small bowl stir together remaining 1 teaspoon orange peel, the orange, pineapple, cilantro, shallot, and jalapeno pepper. Cover and chill until ready to serve or up to 24 hours.
To serve, cut fish into four serving-size pieces, cutting to but not through the skin. Carefully slip a metal spatula between fish and skin, lifting fish away from skin. Serve fish with salsa. Makes 4 servings.