In a mixing bowl, whisk together the mayonnaise, chili garlic sauce, and Sriracha until fully combined and smooth. Cover and refrigerate for up to two days, until you're ready to use it.

In a separate bowl, place the peeled and deveined shrimp in buttermilk and let them marinate for 20 minutes. This helps tenderize the shrimp and enhances flavor.

In a medium bowl, mix together the flour, cornstarch, salt, and pepper to create the breading mixture.

Place a cooling rack over a sheet pan to hold the breaded shrimp before frying—this setup allows the coating to set and become crispier when fried.

Prepare a draining area by lining a separate sheet pan with paper towels, or, if available, place another cooling rack over the sheet pan to drain the cooked shrimp more efficiently.

Preheat your oven to 200°F to keep the shrimp warm between batches.

Once the oil is heating, remove the shrimp from the buttermilk. Working in batches, dredge the shrimp in the flour mixture, making sure they are well-coated. Shake off any excess and place them on the prepared cooling rack to rest while the oil heats up. This helps dry the coating and results in a crispier fry.

Add vegetable oil to a deep, heavy-bottomed pot such as a Dutch oven, and insert a thermometer. Heat the oil over medium-high heat until it reaches 350°F. This process typically takes about 20 minutes.

Carefully add a handful of shrimp to the hot oil. After about a minute, use a slotted spoon to gently stir and separate the shrimp to prevent clumping. Fry each batch for 4 to 4 1/2 minutes, or until the shrimp are golden brown and cooked through.

Once a batch is done, remove the shrimp with a slotted spoon and transfer them to your prepared draining station. Place the drained shrimp in the warm oven to keep hot while you finish cooking the remaining batches. Make sure to allow the oil to return to 350°F between batches for even cooking.

After all the shrimp has been fried, transfer them to a large bowl and toss with 1 cup of the prepared Bang Bang sauce until well coated. Save the remaining sauce for drizzling over the tacos during assembly.

To build the tacos, layer each warmed tortilla with a small handful of shredded cabbage. Add several pieces of the sauced shrimp on top, followed by an extra drizzle of sauce if desired. Garnish with thinly sliced radishes, jalapeño slices, green onions, and chopped cilantro. Serve the tacos immediately for the best flavor and texture.