Rinse the swordfish belly and pat dry with a paper towel. Cut the skin off and cut into cubes.
Heat a cast-iron or steel pan on medium-high heat. Add a teaspoon of Olive Oil.
Sprinkle salt and pepper on the belly cubes.
Add the belly cubes to the pan. Sear on all sides until crusty.
If you have tuna belly, Steve suggests searing each cube for ~20 seconds on each side. You can also grill tuna belly, pectoral side down, with a little garlic, ginger, and soy on top.