Preheat the oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a large mixing bowl, combine the cauliflower florets with olive oil, cumin, coriander, paprika, turmeric, cinnamon, cayenne pepper (if using), salt, and pepper. Toss until the cauliflower is well-coated.
Spread the cauliflower mixture evenly on the prepared baking sheet. Roast in the preheated oven for 20-25 minutes, or until the cauliflower is golden and tender, stirring halfway through.
While the cauliflower is roasting, prepare the tahini sauce by combining tahini, lemon juice, minced garlic, and salt in a small saucepan. Gradually whisk in water until the sauce reaches a smooth and pourable consistency. Set aside.
Assemble the bowls by placing cooked quinoa or rice at the base. Top with roasted cauliflower, chickpeas, cherry tomatoes, cucumber, and red onion.
Drizzle the tahini sauce over the bowls and garnish with fresh parsley or cilantro.
Serve immediately and enjoy your flavorful Cauliflower Shawarma Bowls!