Cut the flank steak with the grain into 2 pieces. Then, cutting against the grain, slice into ¼ inch strips. Tip: If the steak is slightly frozen, not solid, it is easier to cut thinly. Use a good, sharp knife. Place the steak slices in a shallow bowl and add the ginger, cornstarch, 2 teaspoons of soy sauce, 2 teaspoons rice wine or cooking sherry, 1⁄4 teaspoon of the salt and sugar and mix well. Add 2 teaspoons oil and stir. Set aside. In a small bowl, combine the ketchup, hoisin sauce, Sriracha sauce, the remaining 1 tablespoon of soy sauce and 1 tablespoon rice wine.