At the conclusion of a short cross-country flight, the flight instructor and student pilot elected to a perform takeoff and landings at their destination airport. The airport was privately owned, the single asphalt runway was 1,900 ft-long by 24 ft-wide, and there was no taxiway parallel to the runway. The flight instructor stated that, he scanned the runway for obstructions and announced over the airport’s Common Traffic Advisory Frequency the airplane’s position in the traffic pattern and their intent to land. No obstructions were observed during the landing. As the pilots taxied the airplane down the recently-paved runway, a person wearing dark-colored clothing “suddenly” came into view. The person was walking along the runway with his back toward the approaching airplane. The airplane’s left wingtip contacted the pedestrian and knocked him forcefully to the ground, resulting in serious injuries. The airplane’s wingtip incurred minor damage. The flight instructor then stopped the airplane, and he and the student rendered aid to the pedestrian until emergency responders arrived. The flight instructor reported that the pedestrian typically carried a hand-held radio that he would use to listen for traffic calls, but he was not carrying it with him on the day of the accident.