To prepare the Sichuan salt, toast the peppercorns in a pan (without any oil) on low heat for about 2 minutes. Shake the pan constantly to avoid burning the peppercorns. Remove and allow to cool. In the same pan, lightly heat the salt for about 30-40 seconds and then add to the peppercorns. Using a mortar and pestle (or grinder), crush well to get the Sichuan peppercorn salt. If you prefer a fine powder, you may sieve this but I like to use it a bit coarse.
To prepare the marinade for the chicken, mix all the sauces, wine vinegar, sesame oil, ginger and pepper. Add the chicken and mix well; cover and refrigerate for at least 2 hours or longer if possible. Taste and season with salt only if required.
Combine the corn flour with the plain flour in a bowl. Add ½ tsp Sichuan salt to the flour and mix well.
Beat the eggs well in another bowl.
Remove the excess marinade from the chicken and then coat lightly with the flour mixture. Shake off the excess flour before dipping in the beaten egg. Return back to the flour mixture for another light dusting and keep aside.
Heat oil for deep frying and fry the drumsticks in batches till golden brown and crispy. (Remember if the oil is too hot, the outside will brown up quickly without cooking the chicken inside properly).
Serve hot with Sichuan pepper salt.