Combine pineapple juice, lemon juice and salmon fillets in zip-top plastic bag; seal and marinate in refrigerator 1 hour, turning occasionally. Preheat oven to 400 degrees. Remove fish from bag; discard marinade. Combine sugar, chili powder, lemon rind, cumin, cinnamon and salt in a bowl. Rub over fish; place in an 11 x 7-inch baking dish coated with cooking spray. Bake for 12 minutes, or until fish flakes easily when tested with a fork. Serve with lemon slices, if desired.