Heat a large skillet or grill pan over medium-high heat. Brush chicken with oil. Sprinkle with cinnamon and ⅛ tsp. salt. Cook, flipping once, until the chicken is browned and an instant-read thermometer inserted in the thickest part registers 165 degrees F, about 10 minutes.
Meanwhile, combine farro, cauliflower, green and red peppers, broth, lemon juice, and the remaining ¼ tsp. salt in a medium saucepan. Cover and cook over medium heat until heated through, about 8 minutes.
Serve the chicken over the farro and vegetables. Sprinkle with mint and pine nuts. Serve with lemon wedges, if desired.
