Roast and peel the chiles (for more direction, see How to Roast Chiles on Everyday Southwest). Remove the stems and seeds, chop into large pieces and place in a food processor. Add the garlic, pine nuts, cilantro or parsley leaves. Pulse until the chile mixture is coarse, but well minced.
Add the grated parmesan cheese and cumin.
Drizzle the olive oil in while processing the chile mixture to a smooth texture. Start with ¼ of the oil for a thicker, paste type pesto. Add more oil to the pesto if you would prefer a "runnier" texture, add more oil.
Salt and pepper to taste. Adjust with more cumin if desired.