Enjoying the best season of his career on the PGA Tour, Kim Si-woo will tee off at the third major tournament of the season in search of elusive success on the game's biggest stages. Kim will be one of three Koreans in the field at the U.S. Open starting Thursday at Shinnecock Hills Golf Club in Southampton, New York. Kim, a four-time PGA Tour winner, is the top-ranked Korean player at No. 18, the highest position of his career. He has set a car…