Mix the egg white, salt and cornstarch together in a small bowl.
Cut the tenderloins in small pieces (about 1" )and toss them in the cornstarch/egg mixture; set aside. Heat the oil in a heavy skillet or wok until hot. Cook the chicken cubes for 4 - 5 minutes, making sure to toss them so that the pieces separate and brown lightly. Remove the chicken from the skillet to a paper towel. Drain all but 2 tbsp. of oil from the skillet. Heat the oil in the skillet and toss in the green onions, then the Hoisin sauce and then chicken. Stir well before adding the soy sauce.
Serve immediately. .