Hi Thomas.
There are two ways I would do it. First one leave the skin on, it goes nice and crispy. Skin side down in a pan, not to hot until its crispy, then in the oven for a couple of minutes. Try and leave it medium, not nice when well done The other way is sashimi. Bit of soy, lime and wasabi. Really thinly sliced its not as good as blue fin but cheaper. Also the bigger fish aren't as good as the small ones, I think anyway. Or is that just an excuse I use?????
Hope that helps
Alasdair