Grill corn on a grill pan, or just place it in a hot skillet to brown some of the kernels. Remove from pan, allow to cool slightly, then use a sharp knife to cut the kernels off the cob.

Combine all the dressing ingredients in a bowl and stir until combined. 

Place macaroni, corn, beans, olives, tomatoes, green onions, red onion, and cilantro (if using) in a large bowl. Pour 3/4 of the dressing over the top and gently toss until all the ingredients are coated. Add the final 1/4 of the dressing if needed. Cover and allow salad to chill for 2 hours. Serve with garnishments of choice.