How to Make It
Preheat oven to 475°F. Toss cauliflower, pepper, paprika, ¼ cup of the oil, and 1 teaspoon of the salt in a large bowl. (Do not clean bowl.) Spread cauliflower in a single layer on a rimmed baking sheet. Roast, shaking sheet halfway through, until browned and tender, 15 to 18 minutes.
Prepare couscous according to package directions; drain.
Whisk together lemon zest, lemon juice, vinegar, honey, mustard, remaining ½ cup oil and ¼ teaspoon salt in a large bowl. Add cauliflower, couscous, scallions, pistachios, and raisins and toss to combine.