If want want romantic, secluded and on the beach, try the
Cabanas at the Kahala Mandarin. From the website:
With a direct view of the Pacific Ocean, Cabanas Seaside Grill is perfect for intimate dinners and relaxed social gatherings. Guests dine under specially constructed cabanas, with the choice of enjoying the sunset whilst dining, or drawing the drapes for maximum privacy.
The food reviews for this place are good too.
TF