1. Mince green onions and grate ginger.
2. Add green onions, ginger, lime juice, coconut aminos, and red pepper flakes to a shallow dish. Place the flank steak in the marinade for at least 1 hour, or overnight.
3. Steak can be cooked on the grill or on the stovetop. To cook on the stovetop, skip to step 5. To cook on the grill, preheat your grill to high heat.
4. Set the steaks on the grill and allow to sear on each side for 3-7 minutes depending on the level of doneness you desire (rare = 120F, medium-rare = 125F, medium = 130F).
5. Do not take a flank steak past medium as it will continue to cook when taken off the heat source.
6. To cook on the stove, pat the steak surface dry with paper towels. Coat both sides of the steak liberally with salt and pepper. Be generous, you are creating a crust.
7. Add the oil to a cast iron skillet and get the skillet searing hot.
8. Just as the oil seems it will begin to smoke, lay the steak in the pan.
9. Allow to sear on each side for 3-7 minutes depending on the level of doneness you desire (rare = 120F, medium-rare = 125F, medium = 130F).
10. Do not take a flank steak past medium as it will continue to cook when taken off the heat source.
11. For either method, finish by placing the flank steak on a platter to for 10 minutes.
12. Slice into thin strips across the grain and serve.