Flank steak is one of the least fatty, therefore less tender, cuts of meat, but a quick soak in a strong, spicy marinade flavors and tenderizes the meat without any added fat.
Place the steak in a shallow baking dish. In a small bowl, mix the tamari, honey, tandoori spice, and curry paste. Brush the mixture on the steak and let sit at room temperature for 45 minutes or overnight in the refrigerator. Turn once or twice.
Prepare a stove-top griddle or outdoor grill. Grill the steak 5 to 7 minutes per side.
Transfer to a cutting board to rest for five minutes. Cut the steak into 1/4-inch slices and divide among 4 dinner plates.