Lightly brown the mackerel in hot oil in a wok. Remove to paper towel covered plate and cool. It is already cooked, so do not overcook. Once cooled, remove meat from the bones and set aside.
Mash shallots, garlic, and chilies in a mortar and pestle or small food processor container until still coarse, not smooth.
Add shrimp paste, blend in with pestle or process briefly. Or if using dried shrimp, pound or process to break up and blend in to the paste. Blend in the mackerel.
Add fish sauce, lime juice, and sugar (if desired) and adjust seasoning to taste. Serve with sticky rice and steamed vegetables. Serves 4.
*Ask for frozen mackerel in a local Asian market.