In a medium bowl, whisk together coconut milk, curry powder, garlic, ginger, salt, and sugar.

Add chicken thighs to the marinade, coating well. Cover and marinate for at least 1 hour (up to overnight for best flavor).

Remove chicken from marinade and let excess drip off.

Season rice flour or cornstarch with salt and pepper. Dredge each piece of chicken until fully coated.

Heat oil in a deep skillet over medium-high heat. Fry chicken until golden brown and fully cooked, about 5–6 minutes per side.

Drain on paper towels and let rest briefly.

In a small bowl, mix Thai chili sauce with mayonnaise or yogurt until smooth.

Spread sauce on toasted buns. Add fried chicken, cucumber slices, pickled carrots, cilantro, and Thai basil.

Close buns and serve immediately. This Flavor-Packed Thai Fried Chicken Sandwich is best enjoyed hot and crispy.