It's so simple.
1 mackerel (tenggiri), filleted, and deboned.
3/4 tbspn salt, in half a soup bowl of water.
1 tbspn soya sauce
1 tbspn oil
2 tbspn cornflour
White pepper to taste
Shallots and Coriander, handful chopped.
Okay, very imprecise measurements, but it's old school.
Blitz all the fish meat in processor, slowly dribbling the saline solution through the feed tube.
Once the paste starts cohesifying, and forming a ball, pulse in the soya sauce, oil, and cornflour. Add chopped shallots and coriander, and give it another pulse.
You should get a lovely paste, which you can mold into anything you want.