Fire roast the tomatoes and tomatillos on a gas or charcoal grill until the skins have blackened and set aside. The oven is used for the onion and garlic. Be careful not to over toast or the chilies will become bitter. When cool, grind in a spice mill and set aside.
Last step is to add all the above to a food processor.
Be sure to remove some of the blackened skin from the tomatoes and tomatillos, then add to processor with juices. Process until just crushed, now rough chop onions and garlic, break dried chilies into smaller pieces and add to mixture along with cilantro, oregano, cumin and water. Process mixture to a chunky consistency. Add additional salt and sugar to taste. Refrigerate for up to 5 days.