1. Rinse the chicken and pat dry. Cut the wings in half and discard the wing tips. In a bowl, mix the buttermilk with 1 tablespoon of the kosher salt and 2 teaspoons of the chipotle powder. Add the chicken, turn to coat and let stand at room temperature for 20 minutes.
2. In a resealable plastic bag, mix the flour with the remaining 2 tablespoons of chipotle powder, the cayenne and the remaining 1 1/2 tablespoons of kosher salt. Seal the bag and shake to blend.
3. In a large, heavy skillet, heat 3/4 inch of peanut oil to 360°. Working in 2 batches, shake the buttermilk off the chicken, put the chicken in the bag with the flour mixture and shake to coat well. Add the chicken to the hot oil and fry over moderate heat, turning once or twice, until golden and crisp, about 20 minutes; lower the heat if necessary so the chicken doesn't brown too quickly. Drain the chicken on a rack lined with paper towels and serve immediately.
Make Ahead: The recipe can be prepared through Step 1 and refrigerated for 8 hours.