Preheat oven to 425°. Toss together garlic, sweet peppers, oil, salt and pepper; transfer to a parchment-lined 15x10x1-in. baking pan. Bake until dark golden brown, about 15 minutes. Transfer to a large bowl., Meanwhile, in a small saucepan, bring water, oil and salt to a boil. Stir in couscous and quinoa. Reduce heat; simmer, covered, 15 minutes or until liquid is absorbed. Remove from heat; let stand, covered, 5 minutes., Transfer the couscous and quinoa to the bowl with roasted pepper mixture. Stir in the remaining salad ingredients. In a small bowl, whisk dressing ingredients until blended. Pour over salad; gently toss to coat.