Shuck all the oysters and keep refrigerated in their liquor until ready to cook. In a small mixing bowl combine the flour, tapioca starch, salt and baking powder. Beat the egg in a small bowl until frothy. Add the egg to the flour mixture and mix. Slowly add the water to the flour mixture until all the ingredients are combined. Do not over mix. Don’t worry if the batter is still slightly lumpy. Set aside and let it rest for about 30 minutes.
Toast the Sichuan peppercorns in a frying pan over medium heat until fragrant. About ten minutes. Be sure not to burnt the peppercorns. Grind the peppercorns in a spice mill or a blender until completely pulverized. Combine the ground Sichuan peppercorn with the salt and set aside.
Heat the vegetable oil in a wok to about 300 F, or a drop of batter should brown in about one minute. When ready to deep fry drain the oysters thoroughly six at a time. Pat dry on a piece of paper towel then roll them in the dry flour. Then dredge them in the batter making sure they are completely coated. Slowly put the battered oysters in the hot oil and fry them for about two minutes or until golden brown. Turn them over half way through.
Drain the oysters on paper towels. Serve them hot with the Sichuan peppercorn salt as condiment.