Combine tomatillos, chiles, and water to cover in a saucepan. Bring to a boil. Reduce heat, and cook, covered, 5 to 7 minutes or until tender.
Drain. Allow to cool for 5 minutes.Pulse tomatillo mixture, garlic, and next 5 ingredients 3 or 4 times in a blender until chopped. Stir in cheese.*1 large dried ancho chile may be substituted.**Cotija cheese may be substituted for feta. Look for it in Latin markets.