cut into 8 slices Heat oil in large, deep skillet. Add onions and cook until tender but not browned. Place tomatoes in blender or food processor and blend until chopped but not pureed. Add tomatoes and chiles to onion and cook 5 minutes. Add water, salt, sugar and pepper and cook 5 minutes longer. Break each egg, one at a time, onto small plate and slide into hot water mixture carefully so as not to break yolk. Arrange 1 cheese slice on top of each egg. Cover and cook gently 5 to 8 minutes, or until eggs are set and cheese is melted. (C) 1992 The Los Angeles Times