Preheat the oven to 450°F and line a sheet pan with parchment paper. Brush the cauliflower steaks with olive oil and season with cumin, paprika, coriander, turmeric, salt, black pepper, and cayenne. Toss the chickpeas with any remaining oil and spices.
Arrange the cauliflower steaks on the sheet pan and scatter the chickpeas around them. Roast for 20-25 minutes, until the cauliflower is golden brown and tender and the chickpeas are crispy.
Meanwhile, whisk together the tahini, lemon juice, garlic, warm water, and salt until smooth. Adjust consistency with additional water if needed.
Remove the cauliflower from the oven and drizzle with the tahini sauce. Garnish with fresh parsley and pomegranate seeds if using. This exotic, flavorful dish brings Middle Eastern influences to the Mediterranean table.