I'm planning to surprise my partner with a nice tuna steak meal, but have no idea how to cook it or serve it
any suggestions would be appriecated

Just seared on the outside - nice and pink on the inside. With a nice and light red chilli, coriander and spring onion garnish with a small spoonful of fish sauce. Served with noodles or couscous flavoured to your taste - possibly with some coconut milk.

I like to sear my Tuna as Mrs W W says and then let it go cold and serve it in pieces with a mixed bean salad and some gremolata.

David