In a medium bowl, whisk together coconut milk, curry powder, minced garlic, grated ginger, salt, and sugar until well-combined. Add chicken thighs, making sure each piece is thoroughly coated. Cover the bowl with plastic wrap and let it marinate in the refrigerator for at least 1 hour, or overnight for deeper flavor and tenderness.

On a large plate, mix together rice flour (or cornstarch), salt, and pepper. Once the chicken has finished marinating, remove it from the fridge and dredge each piece in the rice flour mixture, ensuring an even coating.

In a deep skillet, heat oil over medium-high heat until it reaches 350°F (175°C). Carefully add the coated chicken thighs to the hot oil, frying them for 5–7 minutes on each side until golden-brown and cooked through.

In a small bowl, combine Thai chili sauce and plain yogurt (or mayonnaise) until completely mixed.

Toast buns until golden, then spread a generous layer of the chili mayo on each half. Layer the fried chicken, cucumber slices, pickled carrots, and fresh herbs on the bottom bun, then place the top bun and serve.