Mix hoisin sauce, vinegar, sugar, ginger, cornstarch, red pepper and 30 ml (2 tbsp.) water.
Cut bok choy leaves in 1 inch strips. Wash and drain. Discard bruised leaves.
Broil salmon about 4 inches below the heat element in the oven, for 6 to 8 minutes. Then cut salmon in 1inch thick slices (optional).
Warm oil in a skillet on medium high heat. Add bok choy, water and garlic; stir-fry for 2 minutes. Add scallions and cook 2 more minutes. Add hoisin mixture, cook 2 minutes longer; then stir in salmon and serve (Optional: Whole salmon fillet may be served over bok choy).