Heat a saucepan on medium heat and roast the black peppercorns and sichuan peppercorns together for 1-2 minutes until you can smell the aroma from the peppercorns. Allow them to cool.
Add salt and sugar, and using a mortar and pestle, crush the spices together to form a coarse powder.
Place shrimp in a large bowl. Add the spices, rice flour and oil, and mix well until the shrimp are well-coated.
Place the shrimp in the airfryer basket, trying to keep them in as flat a layer as possible. You may want to use a rack, and place half the shrimp in the basket and the other half on the rack.
Spray well with additional oil.
Set the air fryer to 325F and cook for 8-10 minutes, tossing halfway through.
Using rice flour makes this recipe perfect for gluten-free and crisps nicely in the air fryer. You could substitute potato flour or corn flour as well.
Rice flour can be found right in the regular grocery store in the flour section.
For those without a mortal and pestle what works well is to put the peppercorns in a zip top bag. You can then bang the peppercorns with a rolling pin or a heavy object to crush them. Just be careful not to break your countertop!