Preheat your oven to 400F (200C). Lightly grease a large baking sheet.
Add the plantains and sweet potato to a bowl with the olive oil and all the spices. Toss to evenly coat. Spread the plantain and sweet potatoes across the baking sheet in a single layer. Bake for 15-20 minutes, flipping once halfway through. They are done when the sweet potatoes and plantains are soft all the way through and browned on both sides.
Fill a tortilla with the sweet potatoes and plantains, and whatever other fillings you like. Rice, black beans, cilantro, etc. Fold over the ends and roll them up so all of the fillings are trapped inside.
To seal the burritos closed, heat a dry pan over medium-high heat. Put your burritos seam side down. Toast the burritos for about 1-2 minutes until golden, then flip and toast the other side. This seals the burrito so that it won't fall open, and the toasted tortilla tastes amazing!