You can walk to Roy's which is located at the Ko Olina golf course (look for reservations on opentable). You can also walk over to the Four Seasons, but I would definitely recommend trying to get reservations first (for Noe and/or Mina's). You can also sit at the bar at Mina's without a reservation. They take walk-ups at Waterman at Four Seasons, but sometimes they only seat Four Seasons hotel guests. You could also try La Hiki at Four Seasons for breakfast or lunch. There is also Tropic Poke at Ko Olina Center.