In a small bowl, combine the first 7 ingredients. Cover and chill until serving., In a large cast-iron or heavy skillet, cook and stir onion in 1 tablespoon oil over medium-high heat until tender. Add garlic; cook 1 minute longer. Add shrimp; cook and stir until shrimp turns pink. Remove from the heat. , In a large bowl, mix the flour, cornmeal, cornstarch, baking powder, salt and pepper. In a small bowl, mix the corn, egg and shrimp mixture; stir into dry ingredients just until moistened., Wipe cast iron skillet clean with paper towels; heat 1/4 in. of oil to 375°. In batches, drop corn mixture by rounded tablespoonfuls into oil; fry until golden brown, 1-1/2 minutes on each side. Drain on paper towels. Serve with sauce.