Whisk up marinade ingredients, add steak and refrigerate several hours or overnight.
Heat cast-iron griddle or skillet, or outdoor grill to medium-high. Drizzle steaks with oil and cook 4 minutes on each side or until crispy at edges and caramelized. Let stand a few minutes then slice against the grain and top with lots of green onions.
For the noodles, bring a large pot of water to a boil and cook pasta to package directions. Drain and cool under cold water; drain again.
Whisk up sesame noodle dressing and toss with noodles to coat.
Serve noodles alongside sliced steak topped with sesame seeds, peanuts, chili pepper, cucumber matchsticks and chives.