Trim 1/2 inch from the stem and blossom ends of tomatoes. Slice tomatoes 1/4 inch thick. Season tomato slices with 2 teaspoons salt and 1 teaspoons pepper; set aside.
In a shallow bowl, whisk together eggs and milk; set side. In a second shallow bowl, whisk together flour, 1/2 teaspoons salt, 1/4 teaspoons pepper; set aside,.
Place panko in a shallow bowl along with cornmeal, remaining teaspoon salt and 1/2 teaspoons pepper; stir to combine and set aide.
Working with one tomato slice at a time, coat tomatoes with flour mixture, shaking off excess. Coat with egg mixture, followed by breadcrumb mixture. Transfer to a wire rack set over a parchment-lined baking sheet; repeat process with remaining slices.
Heat 2 cups oil in a 10-inch skillet over medium-high heat until it reaches 350F on a deep-fry thermometer. Working in batches, carefully place tomatoes into the heated oil in a single layer, Fry until golden, turning once, 2-3 minutes per side. Drain on a paper towel-lined baking sheet. After frying half of the tomato slices, discard oil and heat remaining 2 cups oil in skillet; continue frying remaining tomato slices. Serve tomatoes immediately with aioli.