Preheat a charcoal grill or grill plate.
Thinly slice the beef against the grain, keeping the fat on. Place the soy sauce, lemongrass, fish sauce, pepper and sugar in a mixing bowl and mix until well combined. Add the meat and allow to marinate for 30 minutes.
Meanwhile, place the raw sticky rice in a dry frying pan over medium heat. Cook, shaking the pan frequently until the rice is light golden. Remove from the heat and allow to cool. Using a spice grinder or mortar and pestle, grind into a coarse powder.
Thread the meat onto metal skewers, reserving any marinade. Cook for two to three minutes on each side, or until cooked to your liking. Brush with any reserved marinade while grilling.