Pour 1/2 cup water into a blender jar, and then add the ginger and chiles.
(Adding the water first will ensure a smoother grind.)
Puree, scraping the inside of the jar as needed, until it forms a smooth, light green paste.
Store the paste in a tightly sealed container in the refrigerator for up to 1 week.
(I often divide the paste into smaller containers and freeze them for up to 1 month.
Another option is to freeze 1-tablespoon portions in ice cube trays; when they are frozen, pop them out and transfer them to freezer-safe self-seal bags.)