Baked Sweet Potato Taquitos

small to medium sweet potato (8-12 oz), unpeeled

olive oil

½ cup water

black beans, drained and rinsed

frozen corn kernels (no need to thaw)

ground cumin

½ tsp salt

shredded Monterey Jack cheese

to 22 whole-grain corn tortillas

Sour cream, for garnish

Cilantro, for garnish