How to Make It
Freeze the flank steak and soak 16 wooden skewers for 10 minutes each.
Slice the meat very thinly against the grain and thread onto skewers.
Heat grill to medium-high. Brush the steak with the vinegar and season with ¼ teaspoon each salt and pepper.
Grill until cooked through, 1 to 2 minutes per side. Serve with the blue cheese dressing and sprinkle with the scallions.