In 10 or 12-inch skillet, heat water, lemon slices, onion slices, parsley sprigs, 1/2 teaspoon salt and the pepper to boiling. Boil 3 minutes. Reduce heat to medium-low. Add salmon, skin side down. Cover and cook 5 to 6 minutes or until salmon flakes easily with fork. Remove salmon from liquid in skillet. Cool completely. Cover and refrigerate at least 2 hours but no longer than 24 hours. Discard liquid in skillet.