Why do people go to islands for vacations? They're buying into a lifestyle; the dream that by coming to an island resort they will be able to discard the dinginess and tiredness of city life. They will be able to relax in the sun and become a new, reinvigorated person.
In such luxurious surroundings, you want your guests to feel as if they're being transformed into island treasures. The names I suggest are simple - they should stand alone in the logo. These names should suggest that by coming to this day spa, they can absorb all the radiance of sun-filled island life and take it home with them.
I propose the names:
Gleam
and
Shimmer