1. Place steaks in a large, shallow, nonreactive dish. Slice 3 scallions into thin rounds, and combine with the remaining ingredients except the salt in a small bowl; whisk to combine. Pour marinade over steaks; cover with plastic wrap, and set aside at room temperature 40 minutes, turning steaks once.

2. Heat grill or grill pan. Remove steaks from marinade, letting excess drip off, and pat dry with paper towels. Season both sides generously with salt. Grill until they are well browned on the outside and cooked to desired doneness, or about 6 minutes on each side, for medium-rare. Transfer to a large serving platter; cover with foil, and let rest 10 minutes. Grill remaining scallions, about 1 minute on each side, and serve with the steaks.