I've never actually made this paste. I generally find that having both ginger paste and garlic paste on hand are sufficient for my aromatic flavouring paste needs. The few times that I have found myself in need of ginger chile paste, I've simply pureed a few chiles into some existing ginger paste and called it a day. That said, if you want to do it the "right" way and make sure your proportions are correct and everything, here's how!
Ginger Chile Paste
From 660 Curries
1/2 lb. chopped fresh ginger
12 fresh Thai (bird's eye) chiles
1. Pour 1/2 c. water into a blender jar and add the ginger and chiles.