For the Ancho chile salsa, place the chiles in a dry frying pan over moderate heat. Toast, turning frequently, until the skin blisters and darkens very slightly, 3 to 5 minutes. Remove from the heat.
Bring the water and vinegar to a boil in a medium saucepan. Add the chiles, remove from the heat and let soak 20 minutes to soften.
Place the garlic, half the diced onion, the oregano and cumin in a blender or food processor. Add the chiles and soaking liquid. Blend until smooth. The salsa may be made a day or 2 ahead and then refrigerated.
Preheat the oven to 350 degrees F.
Pour the vegetable oil into a large skillet and heat over medium heat. One at a time, dip the tortillas in the chile salsa and shake off any excess. Transfer the tortillas, one at a time, to the hot pan and saute 10 seconds on each side. Drain on a rack.
Lay all of the tortillas out on a counter. Reserve 1/4 cup of the grated cheese. Divide the remaining cheese into 12 portions and spoon onto the lower half of each tortilla. Divide the remaining diced onion evenly and sprinkle over the cheese. Roll up each tortilla to form a tube.
Arrange the enchiladas on a baking tray, seam side down, and bake 3 to 5 minutes or until heated through. With a spatula, transfer the warm enchiladas to a serving platter. Place about a spoonful of Ancho chile salsa over each enchilada. Sprinkle with the reserved cheese and serve, passing the extra salsa at the table.
In large bowl combine all ingredients and stir until smooth. The dough should be slightly sticky and form a ball when pressed together. To test, flatten a small piece of dough between your palms. If the edges crack, add water to the dough, a tablespoons at a time, until a test piece does not crack.
Divide the dough into 24 golf ball size pieces for tacos and 12 large balls for quesadillas. Place on a platter and cover with a damp towel. Line a tortilla press with 2 sheets of plastic cut from a plastic freezer bag or other heavy duty plastic bag.
Heat a dry cast iron skillet, or non-stick pan until moderately hot. Flatten each ball of dough in the tortilla press, then remove the plastic from the top and, holding the tortilla with your fingertips, peel off the bottom sheet. Lay the tortillas one by one on the skillet and cook about 30 to 45 seconds per side, pressing the top of each tortilla with your fingertips to make it puff. Place the hot tortillas on a towel.
When they are still warm but not hot, stack and wrap in a towel. Serve immediately or let cool, wrap well in plastic or a plastic bag and store in the refrigerator up to a week.
c.1997, M.S. Milliken & S. Feniger, all rights reserved