How to make it
In a large bowl or plastic container, combine the buttermilk, 3 tsp. of the salt, onion powder, and black pepper. Stir until combined. Place the chicken thighs in the buttermilk mixture and toss until coated. Cover and refrigerate for 2 hours or up to overnight.
In a shallow baking dish or sheet tray, combine the flour, garlic powder and remaining 2 tsp. of salt. Stir until evenly distributed. In another shallow dish, pour the Lee Kum Kee Chiu Chow Style Chili Oil.
Pull out one chicken thigh and coat in the flour mixture, pressing down firmly, flipping, then shaking off the excess. Repeat for all thighs.
Fry chicken individually or in small batches at 375°F until brown and crisp and the internal temperature has reached 165°F, about 8 minutes. Remove from hot oil and dip into the Lee Kum Kee Chiu Chow Style Chili Oil and remove, allowing excess to drip off. Drain on a rack or paper towel for 3 minutes.
Toast the inside of the buns in a lightly buttered sauté pan heated to medium heat, about 1 minute. To assemble, spread 1 Tbsp. of Sriracha Mayo on each bun bottom, top each with a seasoned fried chicken thigh, then 5 pickles. Spread 2 more Tbsp. of Sriracha Mayo on each bun top and place on top of the built sandwich and serve.