Combine olive oil and garlic in a small nonstick skillet; cook over medium-low heat 2 minutes or just until fragrant. Remove from heat; set aside.
Bring 2 1/2 cups water to a boil in a medium saucepan. Add couscous and sun-dried tomatoes; reduce heat to medium, and cook 5 minutes or until water is absorbed. Remove from heat; fluff with a fork. Spoon couscous into a large bowl. Add Basic Grilled Flank Steak, cubed mozzarella cheese, roasted red bell peppers, and chopped fresh basil; toss well to combine.
Combine garlic mixture, vinegar, salt, and black pepper, stirring with a whisk. Drizzle dressing over couscous mixture; toss gently to coat. Cover and chill.