Prepare your meat: Remove the tomahawk steak from the refrigerator 45 minutes before cooking. Pat it completely dry with paper towels.
Season generously: Combine the kosher salt, black pepper, and granulated garlic. Coat the entire steak, pressing the rub firmly into all sides, including the thick fat cap.
Prepare the grill: Set up your smoker or kamado grill for indirect heat, targeting a steady ambient temperature of 225°F to 250°F. Add a chunk of hardwood (like oak or hickory) for smoke flavor.
The slow cook: Place the steak on the grill grates away from the direct fire. Insert a meat probe into the thickest part of the center. Close the lid and let it smoke until the internal temperature reaches 115°F (usually 45 to 60 minutes).
Remove and rest: Take the steak off the grill and cover it loosely with foil.
Crank the heat: Reconfigure your grill for direct, high-heat searing (500°F or higher). Let the grates get incredibly hot.
The sear: Brush the steak lightly with avocado oil. Place it directly over the coals. Sear for 60 to 90 seconds per side until a dark, crusty bark forms. Sear the fat cap edges as well.
Final rest: Remove the steak from the grill and let it rest on a cutting board for 10-15 minutes.
Slice and serve: Slice the meat away from the bone, then cut across the grain into thick strips. Top with flaky finishing salt and serve immediately.