Transfer the chile ancho to a glass bowl. Cover with water and cook in the microwave for 7 to 9 minutes, turning halfway through cooking time. Remove from microwave and let cool slightly. Or you can add them to a pot of simmering water and cook them for 10 to 13 minutes.
While the chiles are cooling, in a large nonstick skillet, heat 1 tablespoon of oil to medium heat. Add the beans and bring to a simmer. Drain the chile anchos and transfer to the blender. Add the cumin, oregano, garlic, salt, and ½ cup chicken broth. Blend on high until smooth, set aside.
Add the chile ancho sauce to the beans, stir well to combine. When it comes to a boil, add the remaining chicken broth and reduce heat to a low simmer, stirring often. Taste for salt and while the beans are simmering, mash with a potato masher until desired texture.
Continue cooking the beans until most of the liquid has evaporated. This process requires you to stir often so that beans don't burn on the bottom of pan. It may take up to 35 to 45 minutes. Remove from heat and let cool completely before using as a filling for tamales.