For the passion fruit salsa
Preheat the grill to high.
Slash the mackerel three times down each side, and season well with a good amount of sea salt, probably more than you would normally be inclined to use.
Lay the fish on the grill and place them not too far from the element. Cook for approximately 4 minutes on each side, or until the skin is blistered and browned, taking care not to rip the delicious skin when turning them over. The mackerel should be cooked, but ever so reluctant to pull from the bone without a bit of prompting. If the flesh is just cooked but with a red blood line running along the spine, you have done it perfectly.
While the fish blister, make the passion fruit salsa. Combine all the ingredients in a small bowl and season well with sea salt, tasting a few times.
Remove the fish to 2 plates and spoon over the salsa.
Serve with lime wedges and eat accompanied by cold beer drunk from the bottle, not a glass.