1 Make the marinade/dipping sauce: In a small bowl, combine the soy sauce, lime juice, fish sauce, sriracha, sesame oil, brown sugar, ginger, garlic, and scallions. You will use some of it for the marinade and some for the dipping sauce.
2 Marinate the steak: Place the steak in a shallow dish. Pour 1/3 cup of the marinade over the steak and set the remaining marinade aside to use later as the dipping sauce.
Turn the steak to coat it in the marinade. Let the steak marinate at room temperature for 30 minutes, turning the steak once or twice, or cover it and let the steak marinate for up to 24 hours in the refrigerator.
If you refrigerate the meat, let it come to room temperature before grilling.
3 Cook the rice noodles: Follow the cooking directions on the package of noodles. (Individual manufacturers’ instructions vary.) Drain the noodles in a colander and rinse under cold running…