Refried Beans a la Cantina

Yield:	6 Servings
Categories:	Mexican, Beans

2	c	Dried black beans, or pinto beans
8	c	Water
2/3	c	Lard or vegetable oil
1	lg	Yellow onion, diced
1	ts	Salt
1/2	ts	Freshly ground pepper
		Fresh cilantro, optional