In a mixing bowl, whisk together coconut milk, curry powder, minced garlic, grated ginger, salt, and sugar until combined. Add the chicken thighs, ensuring each piece is well coated in the flavorful marinade. Cover and let the chicken marinate in the refrigerator for at least 1 hour, or overnight for maximum flavor absorption.

On a large plate, combine rice flour with a sprinkle of salt and pepper to taste. Once the chicken has marinated, take each piece and dredge it through the rice flour mixture, pressing lightly to create an even coating.

In a large skillet or deep fryer, heat oil over medium-high heat until it reaches 350°F (175°C). Carefully place the coated chicken thighs in the oil, frying them for 5-7 minutes per side or until they turn golden brown and reach an internal temperature of 165°F (74°C). Once cooked, remove the chicken and place it on a wire rack to drain excess oil.

While the chicken is frying, prepare the spread. In a small bowl, whisk together the Thai chili sauce and plain yogurt until well blended.

Start by toasting your buns. Spread a generous layer of the chili yogurt sauce on both sides of the toasted buns. Then, layer the sandwich with the crispy fried chicken, followed by slices of cucumbers, pickled carrots, and your choice of herbs.

For an added zing, garnish your assembled sandwich with fresh cilantro, a squeeze of lime juice, or a sprinkle of crushed peanuts.