How to Make It
In a bowl, mix the chicken, oil, mayonnaise, grapes, cashews, minced chives, lemon juice and two-thirds each of the shallots and chervil; season with salt and pepper. In another bowl, mix the remaining shallots and chervil with the lemon zest.
Spread the chicken salad on the rye. Cut the sandwiches into halves or quarters. Sprinkle the gremolata on top and garnish with chopped chives.