Slice the steak into thin strips, cutting across the grain to ensure tender pieces. Place the skuced steak and onions in a glass baking dish or a large mixing bowl. In a second bowl, mix together the water, hoisin, chili paste, soy sauce, garlic, and ginger. Pour over the beef and onions. Cover and let marinate for 20 minutes.

Set a large sautéed pan over high heat. Add the steak and onions and cook, stirring frequently, until just browned. Remove from the pan and place on a plate. Reduce heat to medium. Add the pepper, mushrooms, eggplant, and snap peas to the pan, along with any of the extra marinade. Cook, stirring frequently, until the marinade comes to a boil and the peas are defrosted. Add the steak and cook for another 2-3 minutes, or until cook through. Add the Bok Choy; cook 1 minutes or until wilted.

Serve over brown rice.