Cook Kamut according to package directions. Drain, if necessary. Rinse with cold water; drain. Preheat oven to 475 degrees. Line a baking sheet with foil; mist with cooking spray. Combine cauliflower and 1 tablespoon of the oil in baking sheet; toss well to coat. Roast until browned and crisp-tender, about 15 minutes. Combine remaining 1 tablespoon oil, tahini, lemon juice, water, 1/2 teaspoon of the salt, pepper and garlic in a large bowl, stirring well with a whisk. Toss cauliflower with 1 tablespoon of the dressing. Add Kamut and arugula to bowl with remaining dressing; toss gently to coat. Arrange about 1 cup Kamut mixture on each of 4 plates; divide cauliflower and avocado evenly over servings. Sprinkle avocado evenly with remaining 1/4 teaspoon salt.