In a blender, purée the black beans with liquid, garlic, chipotle peppers and water (or chicken stock) until smooth.
Pour the mixture into a skillet and heat until it begins to simmer, stirring occasionally. Season to taste with salt and pepper. Add additional water to thin, if necessary. The sauce should be thin enough for dipping but not watery.
In a small frying pan, add oil to coat bottom of pan and warm over high heat until hot and shimmering, about 2-3 minutes.
Using tongs, dip 1 tortilla in oil for 5 seconds, flip tortilla over and heat for another 5 seconds.
Remove from oil and drain well on paper towels. Repeat with remaining tortillas.
One by one, dip tortillas in enfrijolada sauce, ensuring that both sides are coated.
If desired, stuff with a couple tablespoons of desired fillings such as cheese or chicken and fold in half.
Place enfrijoladas on a plate serve immediately with desired toppings.
Enfrijoladas can be prepared ahead of time and placed in a baking dish. Bake uncovered at 350°F for 15 minutes or until heated through.