In a large mixing bowl stir together the mayonnaise, Thai sweet chili sauce and Sriracha. Use less or more Sriracha depending on how spicy you like your shrimp. This will also impact how dark the sauce is.
Heat 2-3 inches of canola oil in a heavy bottom cast iron pan or skillet until it reaches 350-370°F. Use a deep fry thermometer to monitor the oil. Remove the shrimp from the cornstarch and shake off any excess. Before adding to the hot oil.