Combine the garlic, sugar, and chili-garlic sauce in the bowl of a mortar and mash to a paste. (Or combine them on your cutting board and mash to a coarse paste with a fork and the back of a spoon.) Scrape the paste into a small bowl and stir in the fish sauce, water, and lime juice. Stir well to dissolve the sugar. Transfer to small serving bowls for dipping. Or transfer to a jar, cover, and refrigerate for tip to 1 week.