Step 1Heat the oven to 350 degrees.
Step 2Place the pecans on a rimmed baking sheet and bake until lightly browned, 8 to 10 minutes. Let them cool, then chop.
Step 3Place the turkey, grapes, celery, pecans, green onions and tarragon in a large bowl. Stir in the mayonnaise and mix well. Add salt and pepper to taste. (If you're making this ahead, add the green onions right before serving.)
Step 4Spread a thin layer of cranberry sauce on one side of the rolls or bread, then add the turkey salad. Top with the roll half or another slice of bread, cut into halves and serve.