Preheat oven to 180°C/355°F. Grease a baking dish with olive oil.
Spread ½ cup tomato sauce in the bottom of the prepared baking dish.
Slice sweet potatoes into uniform rounds and arrange first layer slightly overlapping. Season with salt, oregano, and smoked paprika.
Spread 1 can of black beans over sweet potato layer. Season with salt and cumin.
Repeat layering process: add another layer of sweet potato slices, then remaining can of black beans, followed by final layer of sweet potato slices.
Pour remaining ¾ cup tomato sauce over the top layer.
Cover tightly with aluminum foil and bake for 60 minutes, or until sweet potatoes are tender when pierced with a fork.
Remove foil and sprinkle shredded cheese evenly over the top.
Return to oven uncovered and bake for 10-15 minutes until cheese is melted and golden.