Slice the pork into long, thin strips across the grain. Mix the rest of the ingredients, except the oil, together in a large bowl, add the pork and toss to coat well. Cover with clingfilm and leave to marinate in the fridge for at least an hour, preferably overnight, to allow the flavours to develop. Soak 8-12 bamboo skewers in warm water (this will prevent them from scorching under the grill). Meanwhile, make the peanut sauce. Pulse the peanuts in a food processor until very finely chopped (or coarsely ground), then tip into a bowl. Spoon the thick creamy layer of the coconut milk into a saucepan. Heat gently and when the oil separates from the milk, add the curry paste and cook until it is fragrant. Now add the remaining coconut milk and the finely chopped peanuts. Stir in the sugar and tamarind paste and simmer gently, stirring frequently, until the sauce thickens. (If the sauce is too thick, stir in a little boiling water.) Pour into a bowl and allow to cool. Heat up the barbecue, grill or griddle pan. Thread the marinated pork slices on to the presoaked bamboo skewers. Brush with a little oil to prevent them from sticking and drying out and cook for 1½-2 minutes on each side. Serve hot, with the peanut sauce for dipping.