1) In a small bowl combine the white vinegar and 1 teaspoon of sugar, stir until sugar has dissolved then add sliced onions. Allow the onions to sit for 15 minutes then drain discarding the liquid.
2) In a large bowl combine the salt, lime juice and the remaining sugar. Stir until sugar has dissolved, now add the sardines then allow to marinate for 10 minutes.
3)Within 10 minutes the sardines would have been cured from the acids in the lime juice getting slightly discoloured. Gently squeeze the sardines until there is no juice dripping from them then transfer to another bowl -discard the liquid.
4)Add all the sliced herbs, pickled onion, fried Asian shallots, fried garlic chips, garlic oil and dress with dipping fish sauce. Mix well then transfer to a platter.
Garnish with crushed peanuts and chilli.
Whiting is a good substitute for sardines.