If you’re using bamboo skewers, soak them in a bowl of cool water for at least 30 minutes. Make the marinade: In a large bowl, whisk together the tamari, honey, sake, mirin, ginger, garlic and sesame seeds.
Pat the steaks dry thoroughly and cut into ¼-inch-thick strips (we got 14 per steak). Add to the bowl with the marinade, cover and refrigerate for 1 ½ hours. Remove from the fridge and let stand at room temperature for 30 to 45 minutes.
Preheat the broiler to high with a rack 3 to 4 inches from the heat source. Remove the skewers from the water and pat dry. Remove the steak from the marinade and pat dry. Thread the meat onto the skewers, alternating with pieces of scallion. Place the skewers on a cooling rack set over a baking sheet. Broil the skewers until just cooked through and the meat is caramelized in spots, turning once, 1½ to 2 minutes per side.
Place the skewers on a bed of rice and sprinkle with additional sesame seeds, if desired. Serve hot.