Step 1In a heavy pot, combine the water, salt, sugar, spice, garlic and dill and bring to a simmer over high heat. Remove from heat and cool completely.
Step 2Place the thighs in a non-reactive container. Pour the brine over the thighs, keeping the thighs submerged, cover and refrigerate overnight.
Step 1In a large bowl, whisk together the cornstarch, 1 teaspoon cayenne powder (or to taste), and the water to form a slurry. Set aside.
Step 2In a separate large bowl, whisk together the remaining teaspoon cayenne, the paprika, Old Bay seasoning, pepper, flours and salt.
Step 3Remove the chicken from the brine and pat dry. Dip a piece into the slurry. Shake the excess slurry off the piece and dredge in the flour to coat completely. Place the chicken on a wire rack set over a rimmed baking sheet. Repeat with the remaining pieces. Refrigerate the chicken, uncovered, for 1 hour.
Step 4When the chicken is almost ready, heat a deep-fryer or heavy pot filled at least 3 inches deep with oil to a temperature of 325 degrees.
Step 5Fry the chicken, 2 to 3 pieces at a time, until the skin is crisp and golden-brown, the meat is white and firm and a thermometer inserted reads 165 degrees, 8 to 12 minutes. Drain the chicken on a rack, and serve immediately.