Remove seeds, stems and veins from chiles. Soak in cold, salted water about 1 hour. Combine chiles with tomatoes and onion in blender, blend to a smooth paste. Add salt, pepper, and sugar to taste. Heat oil in skillet and cook the puree, over moderate heat, for 3 minutes stirring constantly. Keep warm while making the tacos. Place a strip of cheese with a spoonful of the chile puree on each tortilla, and garnish with a little sour cream. Serve at once. MM and upload by DonW1948@aol.com / CBMC File ftp://ftp.idiscover.co.uk/pub/food/mealmaster/recipes/mmdja006.zip