1. Cook the macaroni according to the package directions. Drain and set aside to cool.
2. Heat an indoor grill and brush with oil. Cook the ears of corn, turning, until browned and cooked through. Cut the kernels off the cobs.
3. Put the corn in a big bowl with the black beans, olives, tomatoes, green onions and red onions and toss to combine.
4. For the dressing in a separate bowl, whisk together the salsa, sour cream, mayonnaise, cumin and salt and pepper to taste. Pour over the salad ingredients and fold together until everything is coated. Taste and adjust the seasoning.
5. Serve chilled.