Remove seeds and stems from dried peppers (I used kitchen shears) and boil in water until peppers are soft.
Remove peppers from water. Discard water. Blend peppers in a food processor using the vinegar for liquid.
Add garlic, cumin, Mexican oregano and black pepper to food process and blend until a smooth paste is formed.
Mix with meat and let stand at room temperature for 4 hours.
Refrigerate for 2 days mixing frequently.
Transfer to storage containers.
NOTE: If you are concerned about leaving meat out at room temperature for four hours, omit this step. I listed this step since this was the orignal recipe and its the one I still follow.______If you do not have a food processor, a blender will work just fine_____I have used ground turkey instead of the pork for a lower fat version. Keep in mind that it will have a bit of a different flavor and will not be as moist. This works well when you are adding the turkey chorizo to other dishes rather then eating by itself.____I put the completed chorizo in freezer containers, seperated by the amount I would use at one time and freeze up to 2 months.___In the recipe I mention getting the pork in a coarse grind--this is when the butcher using a coarse or medium grind disc rather then a fine disc. You can ask the butcher to do this--sometimes they call it a chili grind. But if you can't find this, regular ground pork will be fine. Its really just a texture preference.____If you cannot find the dried chile pasilla, then use all dried ancho chiles. Seems that the dried ancho chile pods are easier to find. But if you can find both, it really does add to the flavor.