Heat a large frying pan or wok over medium heat. When pan is hot, add rice and dry roast, stirring continuously for 10 minutes to prevent burning. Rice will become fragrant and turn from milky white to golden yellow. Continue cooking in the same manner for 10 to 15 minutes more, until rice turns a deep, golden hue. Remove from heat and let cool. Using a mortar and pestle, grind into a course powder. Alternately, you can pulse rice in a food processor until it achieves a coarse consistency. Store in an airtight container in a cool, dark place until ready to use.
Place steak, soy sauce and pepper in a large resealable bag. Seal tightly, squish around to combine and place in the refrigerator to marinate for at least 1 hour, but ideally overnight.
Prepare your grill:
For gas grills, heat the grill with the burners set to high and preheat for 10 minutes. When ready to grill, reduce the burners to medium.
For charcoal grills, fill a grill chimney with charcoal and light it. When the coals are hot (they should be covered with a layer of fine gray ash) empty the coals into the grill and push them to one side of the grill to make higher heat and lower heat cooking zones. Set the grate in place and cover the grill. Preheat the grate for 5 minutes.
Remove meat from marinade, discard liquid and pat meat dry with paper towels. When the grill is hot, cook steaks until they register 105°F for medium-rare or 115°F for medium on an instant-read thermometer, 10 to 15 minutes total. Remove from grill and let rest for 15 minutes.
While meat is resting, whisk together fish sauce, lime juice, sugar and crushed red pepper in a medium bowl. Taste and adjust flavors, if needed. Add red onion, cucumber, tomato and chile to bowl. Slice beef in thin strips against the grain and add to bowl, along with meat juices, cilantro, basil and mint. Toss to combine. Garnish with toasted rice powder and serve immediately.