In a large bowl, whisk together flour, cornstarch and salt; stir in 2 cups ice water until smooth. Beat in eggs just until blended. Stir in shrimp, onions and hot peppers.
In a cast iron or non stick skillet, heat 1 T. of the oil at a time over medium heat. Drop in batter, 1 T. per pancake, and cook, turning once, until top is set and bottom is golden, about 6 minutes. Serve hot or at room termperature with sauce.
Garlic Soy Sauce: In a small bowl, stir together soy sauce, vinegar, oil and garlic; set aside to serve with pancakes.