Preheat a grill or grill pan over medium heat. Toss the cubed sweet potatoes with 1 tablespoon of olive oil and a pinch of salt.
Grill the sweet potato cubes, turning occasionally, until they’re tender and nicely charred on the edges, about 8–12 minutes. If you’re short on time, you can steam or roast them instead, but grilling adds a great smoky flavor.
In a large bowl, combine the grilled sweet potatoes, corn, and black beans.
In a small jar or bowl, whisk together lime juice, lime zest, 2 tablespoons olive oil, cumin, paprika, and a pinch of salt and pepper.
Pour the dressing over the salad. Add red onion and cilantro. Toss gently to coat evenly.
Taste and adjust seasoning with more salt, pepper, or lime juice if needed.
Serve warm or at room temperature. This salad keeps well for leftovers and can be used as a filling for bowls or tucked into tortillas.