In 1988, Petra and Claude Graves’s quest for the perfect wave led them to Sumba, an Indonesian island with one of Asia’s most consistent surf breaks. In 1998 they opened Nihiwatu, a surf resort tucked away among rice paddies, tropical flora, and a 1.5-mile beach ensconced by craggy headlands. Two years ago, the entrepreneurs Christopher Burch and James McBride acquired the resort, determined to develop the property into much more than a surf resort while preserving the area’s heritage and current culture. True…