01 - Place the chicken pieces in a large bowl and pour the pickle brine and hot sauce over them. Cover tightly and refrigerate for at least 2 hours, or overnight for deeper flavor penetration.
02 - In a wide, shallow bowl, whisk together the flour, cornstarch, garlic powder, onion powder, smoked paprika, kosher salt, and black pepper until evenly combined.
03 - Remove the chicken from the brine and discard the used marinade. Pat each piece dry with paper towels. Coat each chicken piece thoroughly in the seasoned flour mixture, pressing firmly to ensure full adhesion. Shake off any excess.
04 - Heat the vegetable oil in a deep skillet or heavy-bottomed pot to 350°F. Carefully lower the dredged chicken pieces into the oil in batches, avoiding overcrowding. Fry for 4 to 6 minutes per side until deeply golden brown and the internal temperature reaches 165°F. Transfer to a paper towel-lined plate to drain.
05 - In a small bowl, stir together the mayonnaise and Dijon mustard until smooth. Spread the sauce generously on both halves of each slider bun. Layer a piece of lettuce, a hot fried chicken piece, and a dill pickle slice on each bottom bun. Cap with the top bun.
06 - Serve the sliders immediately while the chicken is still hot and the coating is at peak crispiness.