In a 12-inch skillet over medium-low, toast the rice, stirring often, until browned and fragrant, 6 to 7 minutes. Transfer to a small bowl and let cool, about 10 minutes; set the skillet aside.

Meanwhile, in a medium bowl, whisk together the lime juice, fish sauce, 1 teaspoon of sugar, ½ teaspoon salt and ½ teaspoon pepper. Stir in the shallots and chilies. Let stand for at least 10 minutes or up to 20 minutes while you prepare the rest of the dish.

Using a spice grinder or mortar and pestle, pulverize the toasted rice to a coarse powder. Return the powder to the bowl and set aside.

In the same skillet over medium-high, heat the oil until shimmering. Add the beef, the remaining 1 teaspoon sugar and ¼ teaspoon salt and cook, breaking the meat into very small bits, until no longer pink, 4 to 5 minutes.

Immediately add the beef and any juices to the shallot-chili mixture, along with the mint, cilantro and half of the rice powder, then toss to combine. Let stand for 5 minutes. Taste and season with salt and pepper, then transfer to a serving platter and sprinkle with the remaining rice powder.