Fijian 'kokoda', Tahitian 'poisson cru', and Hawaiian 'poke' are all delicious variations of the same dish. The Samoan version is oka i'a.
Everything about this dish is according to personal taste, so you'd be hard-pressed to find two people that make it exactly the same.
However, three elements are common across all recipes. Firstly, you need fresh seafood, emphasis on FRESH. How fresh? Well, preferably the specimen you use was swimming in the ocean the same morning of the day you're going to cook. Frozen, canned or any other kind of preserved seafood will just not work for this recipe.
Secondly, you need citrus juice, the acid that flavours and 'cooks' the fish. Samoans commonly use lime or lemon juice. (In South American ceviche, some people use bitter orange, so if you're feeling creative or want to get in touch with your South American side, why not give it a go?) The third element of oka i'a is a selection of vegetables or even just one. If you simply add onions and nothing else, that's still oka.
What follows is a basic recipe, but I encourage you to make it your own. Don't limit yourself to fish. Try fresh mussels, scallops or crabmeat. Add whatever vegetables you like, although crisp and crunchy veges like celery and cucumber provide a nice contrast to the fish. My sister O likes to add a finely minced hot chili pepper for a bit of kick. Some people like to add fresh herbs, cilantro or parsley, and I've also seen oka with lemon slices floating in it. If you have any suggestions for how you put your own twist on oka i'a, I'd love to hear them.
Oka I'a (serves 4)
1 pound (500g) fresh tuna or snapper ½ cup (120ml) lemon or lime juice ¼ onion 2 spring onions 2 medium tomatoes 1 large or 2 small cucumbers 1 cup (240ml) coconut milk salt to taste
Cut your fish into medium dice. Cover with lemon or lime juice and set aside for 1 minute to an hour. Yes, you read that right - 1 minute. My mother doesn't even marinate the fish in the lemon juice, just throws everything together. So it's completely up to you how raw you want your fish. The longer you leave the fish in the citrus acid, the more it's 'cooked' and the texture will be firmer than soft, raw fish. But you will also lose some of the clean, fresh flavour of newly-caught fish.
I marinate the fish for as long as it takes me cut up the vegetables. So this is the next step. Finely dice your onion, slice the spring onion, dice your tomatoes and chop up your cucumber. Everything should be bite-size or smaller.
Drain your fish and discard the lemon or lime juice. Add the vegetables and coconut milk to the fish. Mix well, then season with salt to taste. Refrigerate for at least half an hour to allow the flavours to blend and develop.
Don't worry if your oka looks thick, like it doesn't have much juice. As the oka sits in the refrigerator, liquid from the vegetables will seep out and mix with the coconut milk, and your salad will be juicy in no time.