Heat 1 tablespoon oil in a skillet over medium high heat. Add the sweet potatoes and cook, stirring occasionally, 10 minutes. Add the peppers, cumin, and a pinch of salt and continue to cook an additional 10 minutes, or until the potatoes and peppers are cooked through and tender.
In the meantime, prepare the black beans. Heat 1 tablespoon oil in a small pot. Add the onion and saute 3-4 minutes, until it begins to turn translucent. Add the garlic and saute until fragrant, about 1 minute. Add the beans, lime juice, New Mexican chili powder, and a pinch of salt. Reduce heat to low and simmer about 15 minutes until the beans are heated through and the potatoes & peppers are done.
To assemble, heat the tortillas on a stove burner or over your campfire. Spoon a scoop of beans into the tortilla, add a scoop of the potatoes and peppers, and top with whatever additional fixings you’d like!