Defrost the frozen squid in the refrigerator overnight. Rinse under cold running water, then pat dry.
Score one side of each squid steak in a diamond pattern.
Toast 1/3 cup sesame seeds until golden in a small skillet over medium high heat.
Combine 1 medium shallot, 1 clove grated garlic, 1 tsp grated ginger, 1 tbsp toasted sesame seed oil, 3 tbsp soy sauce and 3-4 tbsp Mirin and mix well to blend.
Place steaks in a re-sealable plastic bag, cover with half of the marinade. Seal the bag and shake to cover all surfaces of the steak.
Refrigerate steaks for 15 minutes or for up to an hour.
Preheat a medium sized cast iron skillet on high heat for about 5 minutes.
Add squid, un-scored side down, and grill for about two minutes, drizzle a bit of marinade on steak while cooking.
Turn steak and grill for another 2 minutes.
Move steaks to a cutting board and slice each steak into 1/2" strips.
Arrange on a platter, drizzle the remaining marinade over the steak slices.
Garnish with green onion and sliced lime, or cilantro and lime or pickled ginger and serve.
