Chop the garlic and chilli pepper, place in a mortar and grate together with the sugar to a paste. Add a good pinch of pepper, the water, the juice of a squeezed lime and the fish sauce and stir everything together until the sugar has completely dissolved. Let the sauce steep for a few more hours.
Go with the amount of chilli to your own taste. The original is quite hot, so if you don`t like it that much, just use half a small pod. By the way, the fish sauce is available in every Asian market and is simply called Fish sauce or Nuoc Mam.
The finished sauce tastes good with any type of spring rolls, wontons, Japanese cabbage pancakes, etc.