Preheat the oven to 425°F (220°C).

In a large mixing bowl, toss the cauliflower florets and drained chickpeas with 2 tablespoons of olive oil, cumin, coriander, paprika, turmeric, chili powder (if using), and salt. Spread evenly on a parchment-lined baking sheet. Drizzle with the remaining 1 tablespoon olive oil. Roast for 25–30 minutes, flipping halfway through, until the cauliflower is golden and tender, and the chickpeas are crispy.

Bring the vegetable broth to a boil in a medium saucepan. Add the pearl couscous and cook according to the package instructions (typically 10 minutes), until tender. Drain any excess liquid if needed, fluff with a fork, and set aside to cool slightly.

In a small bowl, whisk together the tahini, lime juice, water, garlic powder, ground cumin, and a pinch of salt and pepper. Add more water a little at a time if the dressing is too thick.

In a large bowl, combine the cooked couscous, roasted cauliflower and chickpeas, red onion, parsley, and mint. Pour the tahini dressing over the salad and toss gently until well coated.

Serve warm or at room temperature. Store leftovers in an airtight container in the refrigerator for up to 3 days.