In a mixing bowl, combine coconut milk, curry powder, minced garlic, grated ginger, salt, and sugar, whisking well to create a marinade. Make sure the chicken thighs are fully coated in this aromatic mixture, then cover the bowl and refrigerate for at least 1 hour, preferably overnight.

On a large plate, mix rice flour or cornstarch with a pinch of salt and cracked black pepper. Take each marinated chicken thigh, letting excess marinade drip off, and dredge in the rice flour mixture.

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

In a small bowl, combine Thai chili sauce and mayonnaise, stirring until you achieve a creamy, homogeneous mixture.

Begin by toasting the buns until golden brown. Once toasted, spread a generous layer of the spicy mayo on both halves. Next, place a crispy chicken thigh on the bottom bun, followed by fresh cucumber slices, pickled carrots, and a sprinkle of cilantro and Thai basil.