Use this recipe's structure to play with your own flavors. I really like this Japanese take on it, though. You can find togarashi in the Asian sections of most supermarkets in little jars.
Soak the trout in the soy sauce for 2 hours in the fridge. Remove, pat dry (do not rinse) and then slick up the fish with the sesame oil on both sides. Sprinkle the togarashi on the meat side.
Barbecue the trout over a smoky fire at about 225°F for about 1 hour. It's done when the meat flakes off the skin easily, so start checking at about 45 minutes. Serve hot or cold.