Slice the steak against the grain in 1/4” pieces.
Put cornstarch on dish so that you can dip the steak pieces in it. Make sure both sides of beef are covered. Let beef sit in the cornstarch for 10-15 minutes so that it sticks.
While the beef is standing in cornstarch prepare the sauce.
Heat the 2 teaspoons of vegetable oil and 1 tablespoon sesame oil in a sauce pan over medium low heat. Add ginger and garlic, cook for about 1 min. Do not let it get too hot or it will burn. Stir in soy sauce, brown sugar and water then increase the heat to bring to a boil for 3-4 minutes or until the sauce thickens. Remove from heat and set aside.
Heat oil in wok or large frying pan (have enough so that the steak will be mostly covered).
Saute steak until brown and is cooked evenly. Use slotted spoon to take meat out and drain on paper towels to get off the excess oil.
Add the steak into the sauce.
Garnish with green onions.