1. Preheat oven to 400°.
2. Remove giblets and necks from hens. Rinse with cold water; pat dry. Remove skin; trim excess fat. Split hens in half lengthwise. Combine paprika, next 3 ingredients (through pepper), and 1/4 teaspoon chopped thyme; rub on hens.
3. Place hen halves, breast sides up, in a shallow roasting pan coated with cooking spray; place a thyme sprig in the cavity of each bird.
4. Insert a thermometer into meaty part of a thigh, avoiding the bone. Bake at hens at 400° for 35 minutes or until thermometer registers 165°. Transfer hens to a platter; cover with foil.
5. To prepare sauce, place a zip-top plastic bag inside a 2-cup glass measure. Pour drippings from broiler pan into bag; let stand 10 minutes until fat rises to top. Seal bag; carefully snip off 1 bottom corner. Drain drippings into a small bowl; discard fat. Set drippings aside.
6. Heat oil in a saucepan over medium-high heat. Add onion; sauté 3 minutes.
7. Combine broth, port, 1/4 teaspoon chopped thyme, cornstarch, cherries, reserved drippings, and any juices accumulated on platter; add to pan, and cook 5 minutes. Serve hens with sauce; garnish with additional thyme sprigs, if desired.