How to Make It
Heat oil in a large stockpot to 350°F over medium-high.
Whisk together eggs and water in a shallow bowl or baking dish. Whisk together flour, cornstarch, baking powder, salt, and both peppers in another shallow bowl or baking dish.
Place half of fish pieces in egg mixture, turning to coat completely. Shake off excess. Dredge in flour mixture to coat completely; shake off excess. Carefully add fish to hot oil. Cook until golden brown and crispy, 4 to 5 minutes. Drain on paper towels; sprinkle with kosher salt. Repeat process with remaining fish. Serve with lemon wedges.