Freeze steak for 20 - 30 minutes; when slightly firm, slice thinly across the grain. Meanwhile, mix together peanut oil, oyster sauce, curry powder, and brown sugar; set aside. In a small jar, mix together rice vinegar, fish sauce, sugar, and ginger. Combine thoroughly; taste, adjust vinegar and fish sauce to taste and set aside.

Heat sesame oil in a wok or large sauce pan over high heat. When very hot, add the beef and half the oyster sauce mixture; cook, stirring constantly, until the beef is just done. (If it throws off water, push the beef up the sides of the wok (or remove from the pan) and allow water to cook off before finishing cooking beef. Remove beef from pan and keep warm; add cooked noodles to pan, add remaining oyster sauce mixture, toss to coat, and heat through. Remove from heat.

Divide noodles between bowls, top with beef. Garnish as desired; add dressing to taste.