In a shallow casserole dish, whisk together soy sauce, beer, rice vinegar, sesame oil, garlic, ginger and Ac’cent. Add the skirt steak (you may have to cut in half to fit in the dish) and allow to soak in the marinade for several minutes; then flip over. Cover and refrigerate for 2 hours.
Preheat grill. Remove steak from the marinade and place directly over a medium-high heat. Grill on one side for 5 minutes. Flip over and grill for another 5 minutes. Remove from the grill and place on a cutting board to rest for 5 minutes.
Slice the meat on the bias (against the grain of the meat) and sprinkle each serving with sesame seeds and green onions.