In a medium mixing bowl combine turkey, celery, mayonnaise, and pepper. Cover and chill until serving time, if desired.
To assemble, spoon turkey mixture onto a large serving platter. Place salad greens and orange wedges around the turkey mixture. Top greens with red onions. Drizzle raspberry vinaigrette over greens. Top turkey mixture and greens with cranberries and toasted walnuts. Makes 6 servings.