Lay the salmon skin side down on a sheet pan. Run your fingers along the length of the fish to check for pin bones. They will be difficult to see but easy to feel. If they are present, use kitchen tweezers or pliers to pull them out.
Sprinkle the fillet evenly with the salt. Let it sit at room temperature while the oven preheats.
When the oven is ready to go, sprinkle the nutritional yeast evenly over the fillet, then, sprinkle the coconut butter over it, leaving clumps of it here and there. Sprinkle the lemon zest and then the thyme over the fillet, as evenly as possible.
Roast the salmon on the middle rack of the oven for 5 minutes, then set the oven to broil. Broil for 2 to 3 minutes, until the clumps of coconut butter are browned and the fish is cooked through. If you're making king salmon, which tends to be much larger, it may need to cook longer. A good indicator that the salmon is ready is that the meat flakes easily. Test this at 1-minute intervals until the thickest part of the fish easily flakes when pierced with a fork.
Remove the salmon from the oven. Let it rest for a few minutes, then garnish the fillet with the green onion slices. Slice the fillet into as many portions as you need, and lift the pieces off of the skin with a spatula to serve.
Sore leftovers in an airtight container in the fridge for up to 4 days. To reheat, flake and sauté the salmon in a skillet over medium heat for 4 minutes.