Cut sweet potatoes in half and cut a grid in the flesh, then scoop it out. (Note: Some of the pieces will get mashed, some will stay cubed.)
Saute onion in oil over medium-high heat until translucent.
Stir in beans and sweet potatoes and heatthrough.
Meanwhile, combine remaining ingredients in a bowl or jar.
Pour sauce on bean and sweet potato mixture and stir until combined. Mash a few beans or sweet potatoes along the way if you like.
Enjoy with chips, on a tortilla, or over hot rice!