To prepare salad, bring water, 1 teaspoon oil, and salt to a boil in a medium saucepan; gradually stir in couscous. Remove from heat; cover and let stand 5 minutes. Fluff with a fork. Place in a large bowl; cool to room temperature.
Heat a large nonstick skillet over medium-high heat. Add remaining oil to pan. Add the bell pepper, zucchini, and mushrooms; sauté 4 minutes or until bell pepper is tender.
Add bell pepper mixture, chicken, carrot, onions, currants, mint, and black pepper to couscous; toss gently to combine.
To prepare dressing, combine yogurt and remaining ingredients, stirring with a whisk. Drizzle over couscous mixture, tossing gently to combine.