Beaches
Chun's Reef, Haleiwa
Kailua Beach
Kaneohe
Hawaii Kai
Kahala Resort
Kahala Coast
Kalama Beach Club
Heeia State Park
There are no private beaches in Hawaii. (Except military beqaches) You can go to any beach and get married.
All beaches have some sort of  public access.
Waikiki Beach
Pyramid Rock beach