In a mixing bowl, combine coconut milk, curry powder, minced garlic, grated ginger, salt, and sugar to create a marinade. Add chicken thighs and refrigerate for at least 1 hour.

On a large plate, mix rice flour or cornstarch with salt and pepper. Dredge marinated chicken in the coating mixture.

Heat oil to 350°F (175°C). Fry chicken for 5-7 minutes per side until golden brown and cooked through. Transfer to a wire rack to drain.

In a bowl, mix Thai chili sauce with yogurt to make a spread.

Toast buns in a skillet until warm and crisp.

Spread sauce on buns, add fried chicken, veggies, and herbs. Top with the other bun and gently press.

Garnish with cilantro, lime juice, or crushed peanuts before serving.