Heat a sauce pan and add two tablespoon of vegetable oil, add the onion and garlic and fry for 3 minutes, then add the beans with all the juice and add the water. Season with salt and cumin. Bring it to a slight boil and then blend it until it becomes a smooth sauce. Return to the sauce pan and set aside.
Heat the rest of the oil and fry the tortillas one by one. Fill the tortillas with a bit of queso fresco and fold them, place them on a serving platter and when all the tortillas are fried and filled witht the cheese. Pour the bean sauce.
Garnish with more queso fresco and slice onion. Enjoy them with some Mexican rice.