Heat oven to 425ºF and set a large rimmed baking sheet on the middle rack.
In a large bowl, toss cauliflower with 3 Tbsp. olive oil, coriander, turmeric, ½ tsp. of the salt, and black pepper.
Transfer to the hot baking sheet, spread in an even layer, and roast until crisp-tender and browned in spots, about 25 to 30 minutes, tossing once halfway through.
Bring 1 ½ cups water to a boil in a medium (2-quart) saucepan.
Add the couscous and remaining ½ tsp. salt, return to a boil, then cover and reduce the heat to a simmer.
Let cook until the liquid is absorbed, about 15 minutes.
Drain any excess water, and stir in chickpeas.
In a small bowl, combine parsley, lemon juice, garlic, paprika, cumin, and salt.
Gradually stream in olive oil, whisking constantly with a fork, until combined.
In the same bowl you used to season the cauliflower, add couscous and chickpea mixture, along with roasted cauliflower, almonds, raisins, mint, and parsley.
Add dressing and toss to combine.
