01 - In a mixing bowl, combine the chicken pieces, pickle brine, and hot sauce if using. Cover tightly and refrigerate for at least 2 hours or up to 8 hours for deeper flavor penetration.
02 - Remove the chicken from the brine and pat each piece thoroughly dry with paper towels to ensure the breading adheres properly.
03 - In a shallow dish, whisk together the flour, cornstarch, garlic powder, onion powder, smoked paprika, salt, and pepper. Pour the buttermilk into a separate shallow bowl.
04 - Dredge each chicken piece in the flour mixture, then dip into the buttermilk, and return to the flour mixture for a second coating. Press firmly to ensure complete, even coverage on all sides.
05 - Pour about 2 inches of vegetable oil into a deep skillet or Dutch oven. Heat the oil to 350°F, using a thermometer to monitor the temperature for consistent results.
06 - Carefully lower the breaded chicken pieces into the hot oil in small batches. Fry for 3 to 4 minutes per side until golden brown and the internal temperature reaches 165°F. Transfer to a wire rack or paper towel-lined plate to drain.
07 - Lightly toast the slider buns in a dry skillet or under a broiler until just golden on the cut sides.
08 - Spread mayonnaise on the bottom half of each bun. Layer on a lettuce leaf, a piece of fried chicken, and a dill pickle slice. Cap with the top bun halves and serve immediately while warm and crispy.