Seed the papaya, and make slices vertically and horizontally in the flesh without going through the peel. Scoop out the papaya and place in a medium bowl.
Add the remaining ingredients and let sit in the refrigerator for at least half an hour to marinate.
In the meantime you can start the rice and clean the fish.
Put the grill on at high heat for at least 5 minutes.
Grate the zest of the lime and set aside. Rinse the halibut and pat dry. On a platter squeeze the juice of the lime over the fish. Sprinkle the lime zest, cayenne pepper and salt and pepper on top.
Place the fish on a aluminum foil with enough to fold over and seal into a pouch to cook. Place on the grill for 7 minutes on medium heat.
Remove the fish packet from the grill when the fish appears flaky when pressed.
Top the halibut with the papaya salsa and serve with steamed rice that had 1/2 tsp of turmeric put in the boiling water prior.