Preheat oven to 400°F. Line a baking sheet with parchment paper.
In a large bowl, combine the chicken, bell peppers, and onion. Drizzle with 2 tablespoons olive oil and sprinkle with cumin, paprika, ½ teaspoon salt, and ¼ teaspoon black pepper. Toss to coat.
Spread the chicken and vegetable mixture in a single layer on the prepared baking sheet. Roast for 20-25 minutes, stirring halfway, until the chicken is cooked through and the vegetables are tender.
Meanwhile, in a medium bowl, combine the couscous and boiling water. Cover and let stand for 5 minutes. Fluff with a fork.
Add the parsley, mint, lemon juice, 1 tablespoon olive oil, and ¼ teaspoon salt to the couscous. Stir to combine.
Serve the sheet pan kebabs over the couscous salad.
