Coarsely mash the garlic, chilis, and salt with a mortar and pestle or chop by hand. Transfer the mixture to a clean sterilized glass jar or bottle.
Bring the water and vinegar to a boil and then pour over the garlic and chili mixture in the jar. Allow to cool fully then transfer to the refrigerator. The longer the chili pepper sits the better it gets, and it will keep in the refrigerator indefinitely.