Mongolian flank steak starts by making a marinade from one half teaspoon sugar, one teaspoon corn starch, one tablespoon of vegetable oil, one table spoon of soy sauce, one teaspoon of rice wine, and one teaspoon of sesame oil. Stir up the marinade. Cut a three quarter pound flank steak into pieces about one quarter of an inch thick. Put the meat in the marinade and chill it in a refrigerator for one hour. Cut a bunch of green onions into one and a half to two inch pieces. For the sauce, take one half cup of water, and add two tablespoons of ground bean sauce or paste, two tablespoons of hoisin sauce, one teaspoon of cornstarch, and one teaspoon of dry red pepper flakes. Heat a large saute pan with three tablespoons of vegetable oil over medium high. Add the beef that has finished marinating. Cook the beef for about one minute. Then add the green onions and the sauce. Let it come back up to temperature and cook for another minute. Serve with rice.