Step 1: Prepare the Marinade: In a mixing bowl, combine the low sodium soy sauce, rice vinegar, brown sugar, toasted sesame oil, grated ginger, minced garlic, and chili garlic sauce. Whisk together until the brown sugar is dissolved and all ingredients are well mixed.
Step 2: Marinate the Flank Steak: Place the flank steak in a large resealable plastic bag or a shallow dish. Pour the marinade over the steak, ensuring it is well coated. Seal the bag or cover the dish and refrigerate for at least 30 minutes, or up to 4 hours for maximum flavor.
Step 3: Preheat the Grill: While the steak is marinating, preheat your grill to medium-high heat. This ensures a nice sear on the steak, locking in those juicy flavors.
Step 4: Grill the Steak: Remove the flank steak from the marinade, letting any excess marinade drip off. Place the steak on the grill and cook for about 6-8 minutes on each side, depending on your desired level of doneness. A meat thermometer should read 130°F (54°C) for medium-rare.
Step 5: Rest and Slice: Once cooked, remove the steak from the grill and let it rest for 5-10 minutes. This resting period allows the juices to redistribute throughout the meat for a more tender bite. Slice against the grain to serve.