Soak the beans in water for the 8 to 12 hrs. When you are ready to cook them, throw the soaking water away, put the beans and 6 cups of fresh water in a large pot. Cook the beans until tender, about 30-40 min. I like to salt beans when they are done.
In a large skillet, at medium temperature, sauté the onion with the oil.
Mean while with a ladle take out 3/4 of the cooked beans (approximately) and reserve in a bowl. Leave all the cooking water in the pot.
From the 3/4 of cooked beans you took out from the pot, take one part and add it to the skillet with the onions. The onions have to be light brown and soft. Save the other two parts of beans for another day, or even freeze them.
Smash the beans with a potato smasher or a fork until broken and smashed but not pureed. Check for salt and return them to the pot where you cooked them. Put the 3 cups of cooked hominy. Stir a bit and check your season again.
Sprinkle with dry Mexican oregano or fresh cilantro to serve.