Combine chicken thighs with salt, sugar, and white pepper in a bowl. Mix thoroughly to ensure even coating. Cover and refrigerate for 1 hour to allow the seasoning to penetrate the meat and tenderize the chicken.

Place uncooked rice in a dry skillet over medium heat. Toast the rice, stirring constantly, for 5-7 minutes until golden brown and fragrant. Transfer toasted rice to a grinder or mortar and pestle. Grind to a coarse powder consistency-not too fine, as you want texture for crunch.

In one bowl, combine all-purpose flour and rice flour. In a second bowl, mix 3 tablespoons of the flour mixture with 1/2 cup water to create a wet batter with a consistency similar to pancake batter-not too thick or runny.

Remove marinated chicken from the refrigerator. First, coat each piece in the dry flour mixture, shaking off excess. Next, dip into the wet batter, allowing excess to drip off. Finally, dredge again in the dry flour mixture for that signature extra-crispy coating.

Heat oil in a deep pot or wok to 350°F (175°C). Carefully lower chicken pieces into the hot oil. Fry for 6-8 minutes per side, depending on thickness, until deeply golden brown and the internal temperature reaches 165°F. Avoid overcrowding the pan. Transfer to a wire rack to drain excess oil.

In a large mixing bowl, whisk together fish sauce, lime juice, and sugar until the sugar completely dissolves. Add chili flakes according to your heat preference. Stir in sliced red onions or shallots, chopped green onions, and fresh cilantro.

Let the fried chicken rest for 5 minutes, then slice into strips. Add chicken to the bowl with the dressing and toss gently to coat. Sprinkle generously with toasted rice powder and toss once more. Serve immediately while the chicken is still warm and crispy.