Preheat outdoor grill to medium heat.
Cut the cauliflower into “steaks” - remove the leaves from the base (do NOT remove core) of the cauliflower and cut the cauliflower into 4 steaks that are each 1/2 inch thick.
In a small bowl, combine spices (salt and pepper through cayenne). Brush each cauliflower steak generously with olive oil, then season evenly with spice mixture.
Place cauliflower on grill, and cook for 4 to 6 minutes per side or until cooked through.
In a small bowl, whisk together all ingredients for sauce except water. Once mixed well, slowly add water to get desired consistency. Should still be somewhat thick, but thin enough to drizzle.
Serve the cauliflower with the tahini sauce drizzled on top and a spoonful of pomegranate seeds.