How to cook Marlin steaks?
For a quick meal I ususally marinate the marlin in lime juice, salt, a crushed garlic clove and a tiny bit of olive oil. Then I serve it with a homemade salsa - chopped de-seeded tomatoes (I use mini plum tomatoes as they are sweeter), chopped avocado, chopped red onion, a bit of fresh cilantro and lime juice - plus some basmati rice on the side and/or some flour tortillas.
Marinate them and cook them on a well-oiled grill or, preferably, in one of those grilling basket thingies.
I like teryaki but use your favorite marinade, homemade or storebought. Put them on a real hot grill for only a few minutes per side depending on thickness of steak. Enjoy.