01 - Preheat the oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large mixing bowl, combine sweet potato cubes, diced red onion, and minced garlic with olive oil, ground cumin, smoked paprika, chili powder, salt, and black pepper. Toss to ensure even coating. Spread the seasoned mixture in a single layer on the prepared baking sheet.
03 - Roast the vegetables for 25–30 minutes, stirring halfway through the cooking time, until the sweet potatoes are tender and exhibit light caramelization.
04 - While the vegetables are roasting, gently warm the drained and rinsed black beans in a small saucepan over medium heat for 3–4 minutes, stirring occasionally.
05 - Warm the flour tortillas either in a dry skillet over medium heat or in a microwave for 10–20 seconds, until they become pliable.
06 - Distribute the roasted sweet potato mixture and warm black beans evenly among the warmed tortillas. Top each with shredded cheese, spinach or lettuce, salsa, sour cream or Greek yogurt, and sliced avocado if desired.
07 - Fold in the opposite sides of each tortilla, then roll it up tightly from the bottom to form a secure burrito.
08 - For an optional crisped exterior, place the assembled burritos seam-side down in a skillet over medium heat for 2–3 minutes, allowing them to seal and lightly toast.
09 - Slice each burrito in half and serve immediately. Garnish with fresh chopped cilantro if desired.