Dont waste time peeling cipollini individually, the way you would large onions. First, blanch them in boiling water for about 10 seconds. Drain, rinse in cold water and drain again. Trim off the roots and the skins should slip off easily. You can also simply soak the onions in warm water for about half an hour to get the same loosening effect.
For chestnuts in vacuum-sealed jars, we recommend Verfeuille Whole Chestnuts, from the south of France, which are roasted and lightly steamed ($9 for 8 oz; Fairway Market, 212-595-1888) or Trader Joe's Whole Chestnuts, from Spain, which have an intense flavor and luxurious texture that belies their bargain price ($4 for 14 oz).