Place the farro in a medium saucepan and add enough water to cover. Bring to a boil, then reduce heat to medium-low and simmer 30 minutes. Drain off any excess water. Place in a large bowl, then add the black beans, tomatoes, corn, and red onion.
In a small, separate bowl, whisk together the olive oil, Greek yogurt, lime juice, chili powder, salt, black pepper, and cayenne pepper. Pour over the farro mixture, then toss gently to coat. Stir in the fresh cilantro. Serve warm or at room temperature.
To Store. Keep leftover Southwest Farro Salad in the refrigerator for up to three days.
To Reheat. Bring back to room temperature before serving.