Preheat the broiler. Alternately thread the chicken and zucchini onto skewers. Sprinkle with ½ tsp (2 ml) each salt and pepper. Arrange on a lightly greased rack, set on a foil-lined baking sheet.
Whisk 1/4 cup (60 ml) of the juice with the vinegar, oil and remaining salt and pepper. Measure out 2 tbsp (30 ml) and brush over the kabobs. Reserve remaining dressing. Broil, turning as needed, for 10 to 12 min. or until chicken is cooked through.
Meanwhile, bring the remaining juice to a boil in a medium saucepan; remove from the heat. Stir in the couscous, cover and let stand for 5 min. Fluff with a fork. Stir in the mango, red onion and mint. Drizzle evenly with the remaining dressing and toss to combine. Serve kabobs warm with couscous.