Place the chicken pieces in a bowl and cover them with buttermilk, salt, and pepper. Let the chicken marinate in the refrigerator for at least 1 hour.
In a shallow dish, whisk together the flour, cornstarch, paprika, and garlic powder.
Remove the chicken from the buttermilk, allowing excess to drip off, and dredge each piece thoroughly in the flour mixture, pressing firmly to coat.
Heat about 2 inches of vegetable oil in a deep skillet to 350°F (175°C).
Carefully place the coated chicken pieces into the hot oil, ensuring not to overcrowd the pan. Fry for 4 to 6 minutes per side, until golden brown and cooked through (internal temperature reaches 165°F or 74°C).
Remove the cooked chicken and place it on a wire rack set over a paper towel-lined baking sheet to drain excess oil.
While the chicken drains, prepare the Spicy Mayo: In a small bowl, combine the mayonnaise, sriracha, lime juice, and smoked paprika. Mix well until smooth.
To assemble the sliders, lightly toast the cut sides of the slider buns if desired.
Spread a generous amount of Spicy Mayo on both the top and bottom halves of each bun.
Place one crispy chicken piece on the bottom bun. Top the chicken with a pickle slice and a lettuce leaf. Place the top bun on.
Serve immediately.
Notes
For extra crispiness, double-dip the chicken: after the first flour coating, dip it back into the buttermilk briefly, then coat it again in the flour mixture.
If you prefer baking, place coated chicken on a wire rack over a baking sheet and bake at 400°F (200°C) for 20-25 minutes, flipping halfway.
Use brioche or potato slider buns for the best texture to hold up against the sauce.