In a large mixing bowl, combine the mayonnaise, sour cream, vinegar, onion, chives, garlic powder, salt and pepper. Refrigerate.
MAKE THE SALAD:
Fill a large stockpot 3/4 full of water and bring to a boil. Add the macaroni and cook to package directions for al dente (usually 8 to 12 minutes). Once cooked, drain and rinse under very cold water. Drain again. Add the macaroni to the mixing bowl when it is no longer hot. Toss to combine with the dressing mixture.
In a small saucepan cook your corn with some water, bringing it to a boil. Once cooked, strain and rinse under cool water before adding to your bowl of other ingredients.
Add the tomatoes, black olives and cheese to the bowl. Toss gently until all the ingredients are combined and well distributed throughout. Cover and place in the refrigerator for at least 1 hour prior to serving.