Have your fish monger clean (scale, gut and trim the fins of the fish -- or use a pair of kitchen sheers to remove the fins yourself - cut the fish's tail into a V-shape for a nice presentation). Place the fish in a shallow baking pan and set aside.
Mound the minced garlic, scotch bonnet pepper and kosher salt together on a cutting board. Use the side of a chefs knife to flatten and grind the garlic, pepper and salt into a paste. Transfer to a small bowl.
Add the black pepper, scallions, shallots, lime juice and olive oil. Stir to combine and set aside.
Fill the cavity of the fish with thyme sprigs, sliced onions and a few of the limes wedges that have already been squeezed for the juice. Pour the marinade into and over the fish and cover with plastic wrap. Refrigerate for one hour so the flavors can penetrate the fish.
