In a large bowl, combine coconut milk, curry powder, minced garlic, grated ginger, salt, and sugar to create a rich marinade. Add the chicken thighs, ensuring they are fully coated. Cover and let marinate in the refrigerator for at least 1 hour, preferably overnight.

On a plate, mix rice flour or cornstarch with a pinch of salt and pepper. Set this aside while you heat oil for frying.

In a deep skillet, heat oil to 350°F (175°C). Dredge each marinated chicken thigh in the rice flour mixture, shaking off excess. Fry for 5-7 minutes per side or until golden brown and crispy. Drain on a wire rack.

Whisk together Thai chili sauce and plain yogurt in a small bowl until smooth and creamy. Adjust spice level as needed.

Toast the buns until golden brown. Spread Thai chili mayo on both sides of each bun. Layer fried chicken, cucumber slices, and pickled carrots. Garnish with fresh herbs and serve.

Finish with cilantro, a squeeze of lime, or crushed peanuts for extra flavor.