For the fish: In a shallow dish, combine ½ cup of cornstarch with 2 teaspoons of salt and 1 teaspoon of pepper. Set aside.
In a large bowl, combine the flour, baking powder, paprika, remaining 1 cup of cornstarch, 2 teaspoons of salt, and 1 teaspoon of pepper. Gently stir in the cold beer until just combined. Cover and refrigerate the batter until ready to use.
For the tartar sauce: In a medium bowl, combine the mayonnaise, relish, lemon zest, lemon juice, dill, salt, and pepper. Cover and refrigerate until ready to use.
In a large Dutch oven, heat 2 inches of oil to 375°F. Place a wire rack over a baking sheet.
Pat the fish dry with paper towels. Cut the fish into 10 to 12 (3-inch) pieces. Dredge the fish in the cornstarch mixture, shaking off the excess. Working in 3 to 4 batches, coat the fish in the chilled batter. Immediately transfer the battered fish to the hot oil and cook until golden and crispy, 2 to 3 minutes, turning as needed. Transfer the fish to the wire rack and sprinkle with salt.
Serve the fish with the tartar sauce, lemon wedges, and malt vinegar.