Heat oven to 400ºF. Spray 11x7-inch (2-quart) glass baking dish with cooking spray. Remove and discard neck and giblets from game hen. With kitchen scissors, cut hen in half; place halves, skin side up, in baking dish.
In medium bowl, mix garlic salt, chili powder, ginger, cumin and oil. Brush hen halves with 1 tablespoon of the oil mixture. To remaining mixture in bowl, add sweet potatoes, red potatoes and bell pepper; toss to coat. Arrange vegetables around hen halves in dish.
Bake 40 to 50 minutes or until hen halves are fork-tender and juices run clear, and vegetables are tender.