It's similar to a ceviche, but oh so much better. A ceviche is a dish in which fish (usually shellfish) is marinated raw in lime or lemon juice, and the acid in the juice actually cooks the delicate fish.
This dish started with extremely fresh fish, and instead of being marinaded in just an acidic juice, the main component of the marinate was coconut milk, with just a little bit of lemon juice. This combination mellowed out the usually harsh bite of a ceviche and cooked the fish only slightly, giving the already amazing fish an incredible texture and balance of savory, sweet, and sour. The typical counterparts of tomato, onion, and chili were also added, giving it another element of freshness and a spiciness.
This was then served with what the restaurant called "Tongan fries," which were thin-sliced, fresh fried banana chips. So, the chunks of marinated fish sort of became a dip for these wonderful chips, creating an other combination of the tender fish with the crispy banana chips.
It truly blew me away...it was a perfect first dish to experience the amazing seafood that Tonga offers. Me'akai lelei 'aupito! (very good food!)