01 - In a bowl, combine chicken pieces, pickle brine, and hot sauce if using. Cover and refrigerate for at least 2 hours, up to 8 hours for best flavor penetration.
02 - Remove chicken from the brine and pat thoroughly dry with paper towels to ensure the breading adheres properly.
03 - In one shallow bowl, whisk together the flour, cornstarch, garlic powder, onion powder, smoked paprika, salt, and pepper. Pour the buttermilk into a separate shallow bowl.
04 - Dip each chicken piece into the flour mixture, then into the buttermilk, then back into the flour mixture, pressing firmly to ensure full even coverage on all sides.
05 - Pour about 2 inches of vegetable oil into a deep skillet or Dutch oven and heat to 350°F. Use a thermometer to monitor the temperature for consistent results.
06 - Carefully lower chicken pieces into the hot oil in batches, avoiding overcrowding. Fry for 3 to 4 minutes per side until golden brown and cooked through to an internal temperature of 165°F. Drain on a wire rack set over a paper towel-lined plate.
07 - Lightly toast the slider buns in a dry skillet or under a broiler until golden on the cut sides.
08 - Spread a thin layer of mayonnaise on each bun bottom. Layer a lettuce leaf, a piece of fried chicken, and a dill pickle slice on top. Cover with the bun tops and serve immediately while warm.