Line a sheet pan with paper towels.
In a medium bowl, whisk together all-purpose flour, rice flour, baking powder, cayenne, mustard, salt, and pepper. Whisk the beer into the batter mixture until smooth. Place the mixing bowl over a larger bowl filled with ice and water. This makes the batter light and crispy and keeps gluten from forming.
Pour evoo into a large pot or deep fryer. Heat the oil to 350°F.
Dredge pickles in cornstarch. Dip half of the pickles in batter and then in oil, fry until golden brown on both sides.
Transfer to prepared pan. Sprinkle with sea salt.
Serve with dipping sauce.