Skin fish fillet (if any) and clean, pat dry, cut into chunks. In a food processor, add cornstarch, sea salt, water and process fish fillets until smooth, about one minute. You may need to stop the processor once or twice to scrape down the meat to process thoroughly.
Transfer to a big bowl. Using a wooden spoon (I use a pair of chopsticks), stir the fish paste in one direction until the lumps are bouncy. It is important to do the stirring in ONE DIRECTION, this takes about 10 minutes, or the meat won’t turn bouncy.
Add the seasonings, chopped coriander, shredded lime leaves and mix well. Using a greased spoon take a large tablespoonful of fish paste and flatten into a thick disc.
Heat pan and oil over a medium heat, when the oil looks slightly wavy, turn heat down to low. Place fish paste disc/pattie carefully into the oil.
Try not to move patties until the underside has turned golden brown and caramelised, this takes around 3 minutes. Lift and flip patties, and allow the other side to brown.
Serve hot with chilli sauce.