In a medium bowl, whisk together mayonnaise, buttermilk, Parmesan cheese, and vinegar until combined.
In a large bowl, toss together rice, corn, pimentos, ½ cup of the green onions, bacon, basil and dill. Stir in the dressing and toss to coat. Taste and season with additional salt, pepper or fresh herbs. Sprinkle with the remaining ¼ cup of green onions. Serve cold or at room temperature.
