In a bowl, gently mix the crab meat with mayonnaise, chopped shallot, chives, serrano pepper, paprika, lemon zest, and salt until well combined.
Heat vegetable oil in a 9-inch Dutch oven over medium heat, using a deep-fry thermometer to reach 375°F.
In a separate large bowl, whisk eggs until frothy, then gradually whisk in the beer until smooth.
In another bowl, combine flour, cornstarch, baking powder, and salt, then fold the dry mixture into the beer mixture until just combined.
Gently fold the crab mixture into the batter until evenly distributed.
Working in batches, carefully drop heaping tablespoons of the batter into the hot oil, frying until the beignets are golden brown and crisp, about 4 minutes, turning occasionally. Drain on a paper towel-lined plate.
Serve immediately with a squeeze of lemon juice and enjoy!