Thaw fish, if frozen. Rinse fish; pat dry with paper towels. Finely shred 1 teaspoon peel from lemon; set aside. Squeeze juice from the lemon and orange; combine juices. Measure 1/4 cup juice for dressing and set aside.
Pour the remaining juice into a large skillet; add water. Bring to boiling. Add salmon; reduce heat to medium. Simmer, covered, for 4 minutes. Lay asparagus atop salmon (see Tips). Simmer 4 to 8 minutes more or until fish begins to flake when tested with a fork and asparagus is crisp tender.
Meanwhile, in a small bowl combine reserved 1/4 cup juices, snipped parsley, butter, reserved lemon peel, salt and pepper.
To serve, drizzle dressing mixture over salmon and asparagus. Garnish with additional fresh parsley leaves, if desired.
Tips: Asparagus in the liquid may take on a slightly olive green color.
1 vegetable, 3 1/2 lean meat, 1/2 fat