Salsa: Dice and roast tomatillos and red onion into uniform pieces. Place in bowl with minced garlic, salt, and pepper. Let sit at room temperature for one hour. Add hot sauce and lime juice to taste. Wash cilantro, spin dry, and finely chop. Add to tomato and onion mix. Let sit at least 20 minutes or more before serving.
Anaheim chilies: Remove stems, cut lengthwise, and remove seeds and inner membrane. Grill chilies on high, heat skin side down, until nearly all skin is blistered and brown. Remove skin. Place in bowl and cover with foil to let steam 15 minutes. Peel skin. Caution: Keep hands and fingers away from eyes until washed.
Halibut: To prevent fish from sticking, rub grill grate with olive oil. Turn grill on and preheat to high. Carefully add oil again just before placing halibut. Dry halibut then use one hand to rub with olive oil; the other, to coat with rubbing spices. Rubs such as Halibut Cove Fish Rub can be purchased at the Waterfall Resort General Store or specialty markets.
- Place halibut on an oiled grill at an angle. Lower heat to medium high. Cook 3–4 minutes, checking grill marks by lifting corner.
- To create crisscross grill pattern, rotate fish 45 degrees and cook another 3 minutes. Carefully turn fish over and cook 4–5 minutes more on second side. Don’t overcook. Fish needs about 10 minutes total cooking time; less if it’s thin.
- Serve hot topped with tomatillo salsa.