Notes: If making up to 3 days ahead, cover and chill. If the tiny fiery chilpequín and chiltepín are unavaliable, use 1/2 cup of another dried hot chili such as chiles de árbol; discard stems and seed before toasting.
In an 8- to 10-inch frying pan over medium heat, stir chilies in oil until chilies smell toasted, about 3 minutes; take care not to scorch. Pour from pan into a blender.
Add garlic and 1/2 cup water. Whirl until a smooth purée. If desired, thin with 1 or more tablespoons water. Add salt to taste.
Nutritional analysis per tablespoon.