(Note: Google insists this is Kamuela, it is Kohala) The lava coast of Kohala on the Big Island is dramatic. Waves dash against the black rocks relentlessly until eons from now they will be sand. True, there are fewer white-sand beaches per square foot of land on the Big Island than others in the Hawaiian chain, but the island is huge. Beaches here often hold secrets, are the sources of legends, and are part of the circle of life for creatures indigenous to Hawaii.
There have been lava flows since the ahapua’a land divisions were formed, but from the very tops of the mountains running to the sea, most beaches remain intact. One of my favorites is in a little inlets fronting the Mauna Lani Bay Hotel on Makaiwa Bay called Keiki Beach. Not for much swimming, it is a sandy-bottomed dipper's delight or, as the name states, a place for children (keiki) to play in.
A tree for shade, sand, tide pools to explore, a canoe house (hale) covering a koa canoe nearby, and a friendly turtle (honu) who feeds here are all part of what could be a perfect day. There is surf off the point in winter and snorkeling in other seasons. You might even want to rinse off and have lunch at the Mauna Lani pool restaurant. Parking is a good 15 minute walk via a trail.
Follow signs to public parking off Mauna Lani Drive, bring water and beach gear, and get there early. Of course you could stay at the Mauna Lani Hotel and Bungalows too. http://www.maunalani.com/