Preheat the oven to 400°F. Place butternut squash, sweet potatoes, and red onion in a large roasting pan and toss with 2 tablespoons coconut oil, lemon zest, 1 teaspoon salt, and garlic powder. Roast approximately 30 minutes or until vegetables are lightly browned and tender.

While the vegetables are cooking, prepare riced cauliflower. Heat remaining 1 tablespoon coconut oil in a sauté pan over medium heat. Add frozen cauliflower to pan. Cover and let cook for 8-9 minutes. Toss gently. Add salt to taste. Let cool slightly while vegetables finish cooking.

When vegetables are done cooking, cool about 10 minutes. Mix arugula, cooked cauliflower rice, roasted vegetables, and pepitas in a serving bowl. Add tahini, lemon juice, and remaining salt and toss until vegetables are coated. Top with sliced avocado. Serve at room temperature.