This is a great side dish using fresh ingredients. There are never leftovers!
Preheat oven to 450 degrees F (230 degrees C).
Spread sweet potatoes onto a rimmed baking sheet. Drizzle 1 tablespoon olive oil over sweet potatoes; season with cumin, red pepper flakes, salt, and pepper. Toss sweet potatoes until evenly coated.
Roast on the lower rack of the preheated oven, stirring halfway through, until sweet potatoes are tender, 25 to 35 minutes.
Whisk remaining 2 tablespoons olive oil and lime juice together in a large bowl; season with salt and pepper. Add sweet potatoes, black beans, onion, and cilantro; gently toss to coat.
Per Serving: 291 calories; protein 8.4g; carbohydrates 42.2g; fat 10.6g; sodium 461.8mg.