For the beans we had with the pork burritos, I just did this:
3 cans black beans, drained
1 7-oz can tomato sauce
Chopped onion (I have frozen chopped onion I buy from the grocery store)
1 Tablespoon minced garlic (from a jar)
I covered a pan with a dash of oil, enough to cover the bottom of the pan lightly and sauted the onions and garlic together. Then I add the beans and tomato sauce and cooked it on medium heat until the sauce thickened.