Soak a cedar plank in water for 30 minutes.
Meanwhile, season the Spam slices liberally with the rub.
Fire up your grill for direct and indirect cooking. Once it gets hot, place the plank over the flames and char it on both sides. Keep a spray bottle of water on hand in case the plank catches on fire.
Transfer the Spam to the plank and move it to indirect heat. Cook 20-25 minutes or until lightly charred along the edges. Cook longer if eating directly from the plank.