Line a 6-quart slow cooker with a disposable slow cooker liner. Lightly coat liner with cooking spray; set cooker aside. Add chicken, onion, and garlic to the slow cooker. Add curry powder, ginger, salt, and pepper; toss to coat. Stir in beans, tomatoes, broth, and bay leaf. Cover and cook on low-heat setting for 8 to 10 hours or on high-heat setting for 4 to 5 hours.
Stir lime juice into chicken mixture. If desired, stir in spinach; let stand for 2 to 3 minutes or until spinach starts to wilt. If desired, serve in bowls with hot cooked rice.