Arrange the chicken in an even layer in a large baking pan.
Sprinkle evenly with kosher salt, top with sliced onions.
In a small bowl whisk together the buttermilk, beer and sriracha, pour evenly over the chicken, cover and refrigerate for 8 to 24 hours.
In a medium sized bowl stir together the flour, brown sugar, chili powder, onion powder, salt, pepper, and cayenne.
One at a time remove the chicken pieces, dredge in the flour mixture then gently re-dip in the buttermilk/beer marinade and recoat with the flour mixture (double coating of the flour mixture will give you a crispier chicken), set on a wire rack that has been set over a baking sheet.
Allow the coated chicken to sit at room temperature for 10 to 15 minutes.
Preheat oven to 250.
Add the oil to a large pot until about 6 inches deep, heat to 350 degrees using a cooking thermometer clipped to the pan, adjust heat to maintain that temperature.
Working in batches fry the chicken until golden brown and cooked through (between 4 and 12 minutes each, depending on how thick the chicken and if the piece has a bone in it, use a meat thermometer to check for doneness).
Once each piece is done, return to the wire rack and place baking sheet in the oven while the remainder of the chicken is cooking.
Whisk together the honey and sriracha, drizzle over the chicken just prior to serving (alternately, it can be used as a dipping sauce).