In a mixing bowl, combine coconut milk, curry powder, minced garlic, grated ginger, salt, and sugar. Coat the chicken thighs thoroughly, cover and refrigerate for at least 1 hour or ideally overnight.

In a shallow dish, mix together rice flour, a pinch of salt, and pepper. Remove the marinated chicken from the fridge and dredge each piece in the coating mixture.

Heat vegetable oil in a deep skillet to 350°F (175°C). Fry the coated chicken pieces for about 5-7 minutes on each side until golden-brown.

While the chicken cools, mix together Thai chili sauce with plain yogurt for a zesty spread. Slice cucumbers and wash fresh herbs.

Spread chili-yogurt sauce on each bun, add fried chicken, sliced cucumbers, pickled carrots, and fresh herbs. Complete the sandwich with the top bun.

Serve the sandwich warm, garnished as desired.