In a large bowl mix together mayonaisse, Sriracha, chili sauce and vinegar. Whisk together well, then cover and refrigerate for later. Wash and chop lettuce and onions at this time as well and refrigerate also.
Peel and devein shrimp. Then place in corn starch lightly dredging then press Panko bread crumbs into shrimp. Lay on a large platter and refrigerate for at least 45 minutes. This will let the coating set.
Heat oil over medium heat in a large nonstick skillet, tip oil should be about 1 inch deep. when you can smell the oil it is hot enough to cook shrimp. If you are unsure drop one panko crumb into oil if it bubbles up good it is ready. Add shrimp and cook for a total of 4 minutes turning halfway through. Remove with a slotted spoon onto a paper towel lined platter to absorb the excess oil.
Immediately after draining the shrimp toss in the mayo mixture and serve on top of the lettuce and granish with the spring onions. Enjoy while they are hot. You may also make shrimp tacos with this recipe.