Slice flank steak along the grain into 2" strips. Then slice across the grain into 1/4 inch matchsticks. Toss with 1st marinade and let sit 5 minutes. Toss with 2nd marinade and let sit a half hour
Put about 2 teaspoons of oil in a large frypan over high heat. When oil begins to smoke, add a single layer of meat. Allow to get a good brown on without moving. Turn to finish cooking on all sides. Set cooked portion aside and continue with next batch, until beef is done. Don't over crowd and add more oil as needed.
Slice the whites of the scallions thinly and the green part into 2 inch pieces. Keep the 2 parts separated. Add some more oil to the pan, still on high heat, and add sliced peppers and the scallion greens. I added some par-boiled broccoli at this point too. Salute until the peppers are crisp tender. Add to the mead.
Heat some more oil in the same pan and add the garlic, ginger, and scallion whites. Cook till it starts to brown, around a minute. Return meat and veggies to the pan and toss. Add the sauce and cook over high heat until the sauce thickens Serve.