Put all the ingredients for the fishcakes, except the oil, in a food processor with seasoning and blitz until really well blended. Shape into 12-18 round patties, then chill for up to 1 day until ready to serve.
Wash the food processor, then blitz all the sambal ingredients together to make a bright green, wet paste. Season and chill.
When ready to serve, fry the fishcakes in the oil for a few mins on each side until golden – they will be firm, like Thai fishcakes rather than those made with potato. Pile onto a platter with a bowl of the sambal to serve with drinks, or plate up and serve as a starter.