In a bowl, combine soy, sherry, hoisin sauce, cornstarch, the 1 teaspoon salad oil, sesame oil, sugar, and pepper.
Add chicken and marinate for 30 minutes.
Cut ham, if used, in matchstick pieces.
If you use Chinese sausages instead, steam them on a rack over boiling water for 15 minutes, then cut diagonally in slices 1/8 inch thick; you should have 30 slices.
Cut green onions in 1 1/2 inch lengths, then slice lengthwise in thin shreds.
Cut cooking parchment into 30 5-inch squares.
To wrap chicken, see illustration below .1.
In center of each parchment square, place 1 piece chicken, 3 strips ham (or 1 slice Chinese sausage), several shreds of green onion, and a leaf of coriander.
Turn one corner up over filling.
Fold adjacent corners in toward center, overlapping and enclosing filling.
Fold filled part of packet in half (see dotted line).
Slide fourth corner all the way down into space between layers of paper to seal each packet.
At this point you can cover and refrigerate up to 6 hours until ready to cook.
In a deep pan (at least 6 inches in diameter), pour salad oil to a depth of 1 1/2 inches and heat to 350° on a deep-frying thermometer.
Fry 4 to 6 packets at a time, turning occasionally, for 3 minutes or until chicken is opaque.
Remove with a slotted spoon and drain on paper towels.
Keep warm in a 200° oven until all are cooked or arrange packets in a single layer in a shallow, rimmed baking pan.
Bake in a 400° oven for 12 minutes.