Heat a wok or heavy frying pan to a medium heat. Toss in the peppercorns and the salt and stir-fry until the mixture begins to smoke slightly and brown alittle. Then grind it, using a blender, a clean coffee grinder or a mortar and pestle. The mixture can be made days before you use it. If you make it ahead, be sure it is well sealed in a jar until you are ready to use it.