Place chicken breasts on a cutting board, cover with plastic wrap  or parchment paper and pound a little bit. Then, cut each chicken breast in half crosswise, using a sharp knife. You will get two pieces of chicken.

In a medium bowl combine buttermilk, onion powder, garlic powder and paprika. Add the chicken breasts  and marinate for at least 30 minutes or overnight in the fridge.

In a large skillet or pot heat enough vegetable oil  for deep frying over medium heat until the temperature reaches 350 F/175 C.

Combine all the ingredients for coating in another bowl (all purpose flour, corn flour, rice flour, paprika, garlic powder, onion powder, cayenne pepper, taco seasoning and salt). Add 3-4 tablespoons of buttermilk marinade into the flour mixture and whisk.

Take a chicken piece and dredge in the flour mixture, pressing the flour to form a thick crust. Deep fry in hot oil for 3-4 minutes per side or until the internal temperature reaches 165 F/ 73 C.  The coating should be crispy and golden in color. Don't over cook! Otherwise you will end with a burned coating. Once chicken is cooked, transfer to a wire rack.

Combine all the ingredients for spicy mayo (mayo, hot sauce, garlic powder, paprika and taco seasoning). Keep aside.

In a large non stick pan melt 1 tsp of butter and toast buns until golden. Transfer to a plate, spread a generous amount of spicy mayo on each bun, then top with sliced pickled cucumbers  and chicken. Serve immediately  with some extra spicy mayo.