Add the rice to a wok or large skillet over medium heat, and stir continuously for 5-7 minutes until the rice turns light brown. Using a mortar and pestle or spice grinder, grind the rice into a fine powder. Set aside.
Place a wok or skillet over high heat. Once the pan starts smoking, add the ground chicken and break up the chicken into finer bits using a spoon. Continue cooking the chicken until it browns, about 6-8 minutes. Then add the fish sauce, sugar, lime juice, and water and stir for another minute.
Remove the chicken from the heat and stir in the cilantro, mint, scallions, shallots, chilis, and rice powder.
Salt to taste and serve the larb gai in lettuce cups or with sticky rice.