In a large mixing bowl, combine the corn, tomatoes, scallions, avocado, and cheese. Toss gently. Add the lime juice and oil and toss to coat. Season with white pepper to taste. Garnish with cilantro or parsley.
Refrigerate for 2 hours to allow flavors to blend, but this salad is equally good served immediately. Refrigerate leftovers for 2-3 days.