Soak 8 wooden skewers in water for at least 10 minutes. Heat broiler.
Season the chicken with the paprika and cumin. Thread onto the skewers with the bell pepper and zucchini. Drizzle the chicken and vegetables with the oil and season with ½ teaspoon salt and ¼ teaspoon black pepper. On a rimmed baking sheet, broil the kebabs, turning once, until the chicken is cooked through, 15 to 18 minutes.
Meanwhile, place the couscous in a large bowl and pour 1½ cups hot tap water over the top. Cover and let stand for 5 minutes; fluff with a fork. Sprinkle with the mint and serve with the kebabs.