Peel the celtuce and cut them crosswise into slices of about 1/8 inch thick. Put the celtuce slices in a medium bowl and sprinkle with the salt. Stir the celtuce well to make sure the salt is applied evenly, and let it marinate for about 30 minutes at room temperature. At this point the most of the liquid will have bled out of the celtuce and collected at the bottom of the bowl. Squeeze as much of the remaining liquid out of the celtuce as possible and discard all the liquid.
Sprinkle the 1 tablespoon sugar over the celtuce and mix well. Let the celtuce marinate for another 30 minutes at room temperature. As with the salt, a pool of liquid will form at the bottom of the bowl. Once again squeeze out as much of the remianing liquid as possible and discard all the liquid.
Add the ingredients for the soy pickling brine to the celtuce, and mix well. Transfer the celtuce and brine to a storage container, cover, and refrigerate at least overnight or up to a month.
To store the pickle for a longer period of time, put the pickle in two 8-ounce pickling jars and cover tightly. Process the jars by placing them in a pot of hot water enough to submerge the jars for up to 2 inches in depth. Cover the pot and bring the water to a boil and heat the jars for about 10 minutes. Turn off the heat and let the jars cool slowly. Remove from the pot and store the pickle on the shelf for up a year.