My Brazilian friend makes this for me occasionally and it is fabulous!
Heat 1 tablespoon vegetable oil in a skillet over medium heat, stir in garlic and onion, and cook a few minutes until the onion softens and turns translucent. Remove the onion, and place into a saucepan. Pour the remaining 1 tablespoon vegetable oil into the skillet, and place over medium-high heat. Add cubed pork, and cook until well browned.
Meanwhile, pour 3/4 of the black beans along with 1/4 cup water into the bowl of a blender, and pulse until finely chopped, but not quite smooth. Pour whole beans and bean puree into saucepan along with pork cubes, chicken stock, chorizo, and bay leaves. Bring to a boil over medium-high heat, then reduce heat to medium-low, cover, and simmer 30 minutes. Season to taste with salt and pepper before serving.