Place oil in a medium saucepan fitted with a deep-fry thermometer. Heat to 350°.
In a large bowl, whisk cornstarch, 1/2 tsp of the salt, the pepper and cayenne. In a second bowl, whisk flour and cold water. Place panko in a third bowl and season with remaining 1/2 tsp salt. Toss wing pieces in cornstarch mixture to coat.
Working in batches, dip wing pieces in flour batter, turning with tongs to coat completely. Lift from batter, allowing excess to drip back into bowl. Toss in panko and place on a wire rack set over a baking sheet.
Fry 8 wings at a time in hot oil for 6 minutes. Return to rack and repeat with remaining wings, allowing oil to return to 350° before adding next batch. Fry 6 more minutes per batch, until wings are golden, crispy and cooked through. Place on a paper-towel-lined baking sheet. Serve with BBQ sauce on the side, for dipping.