Mix together the coconut cream, curry paste, sugar, lime juice and fish or soy sauce in a non-metallic bowl. Cut the pork into about 2.5cm/1in cubes and stir into the sauce. Leave to marinate in the fridge overnight or for about 2 hours at room temperature, stirring every so often.
To make up the kebabs, thread pieces of pork on to six long metal skewers, alternating with red onion and lime wedges until all have been used up.
Place the kebabs over medium-hot coals for about 10 minutes, brushing generously with any marinade for the first 5 minutes, and turning every so often until golden and succulent.