In 12-inch nonstick skillet, heat oil over medium-high heat. Add halibut, onion, garlic, gingerroot and asparagus; stir-fry 2 to 4 minutes or until fish almost flakes with fork.
Carefully stir in remaining ingredients. Cook 2 to 3 minutes, stirring frequently, until heated through and fish flakes easily with fork. Serve with additional reduced-sodium soy sauce if desired.