How to Make It
Heat a grill pan over medium-high heat. Coat with cooking spray. Sprinkle lamb with 1/4 teaspoon salt and 1/4 teaspoon pepper. Add to pan; cook 5 minutes on each side. Remove from pan; let stand 5 minutes.
Heat farro according to package directions. Drain and spread out on a baking sheet to cool slightly.
Combine remaining 1/4 teaspoon salt, remaining 1/4 teaspoon pepper, rind, and next 6 ingredients (through thyme) in a small bowl.
Combine farro and arugula in a bowl. Add half of dressing; toss to coat. Divide farro mixture evenly among 4 serving plates; arrange 2 lamb chops on each plate. Drizzle remaining dressing over lamb.