Arrange the tomato slices in a single layer on several sheets of paper towels. Salt both sides of the tomatoes and let stand for 10 minutes. Blot the tomatoes dry after 10 minutes.
Make the remoulade sauce. Cover and refrigerate until ready to serve.
Make a dredging station. Stir together the flour, garlic powder, paprika, and pepper in a shallow dish. Place the buttermilk in a shallow bowl and the cornmeal in a separate shallow bowl.
Dredge the tomatoes in the flour, followed by the buttermilk, and then in cornmeal and gently shake off the excess. Place the dipped slices in a single layer on a wire rack.
Pour the oil to a depth of 1 inch in a deep cast-iron skillet. Heat the oil to 350°F. Cook the tomatoes, in batches, 2 minutes on each side or until golden brown and crispy. Remove to a wire rack to cool. Sprinkle the tomatoes with salt while hot.
Remove the tomatoes to a platter and serve hot with the remoulade.