Mash the tofu to yield about 3/4 cup. To make the filling, combine mashed tofu with the minced ingredients, salt, soy sauce, and sesame oil.
To make the wrappers, mix flour and water by hand, kneading just enough to make a ball of dough.
Cover and let rest for at least an hour. Place on a lightly floured board, and knead for 2 minutes or so.
With palms of your hands, roll it into a long, cylindrical shape, 12 inches inches long, 1 inch in diameter. Cut crosswise into 1/2-inch pieces; you will have 24. If your climate is dry, keep the dough covered.
Shape these, cut-side up, into a round shape. Flatten them with the palm or heel of your hand on a flour-dusted board. With a pastry roller, small rolling pin, piece of dowel, or even an empty jar -- all of these should be wielded under the palm of your hand -- roll each into a round wrapper, 3 inches in diameter, thicker in the center, thinner toward the edge. This is easily done by rolling the pastry roller from the edge of the piece of dough to the center, and back again, turning the dough counterclockwise a little with your left hand after each roll.
Continue all the way around several times, also turning the dough over once or twice, until you have a thin, 3-inch wrapper. To assemble, place 1-1/2 teaspoons filling (or as much as the wrapper will hold) in an elongated mound in the center of each wrapper; fold the dough over the filling so that the edges meet.
Press the edges together for a tight seal, at the same time making four or five tiny pleats, pinched tightly flush with the edge. Be sure that it is completely sealed to keep the water out and the filling in. (With commecial wrappers, it may be necessary to moisten half of the inside edge first to get a seal.)
Bring 4 cups water to the boil in a pot. Immerse eight dumplings at a time for 3 minutes (add an extra minute if frozen -- do not defrost them first). Lest they break open, add a little water to slow the boil whenever it becomes too rapid.
Stir occasionally in case some of them stick to the bottom (true to their name). After 3 minutes, remove the dumplings with a slotted spoon.
Cook the remaining two batches in the same way. Serve hot, accompanied by small dipping saucers of soy sauce and vinegar (cider or Chinese dark), mixed in roughly equal proportions, or to taste, and thinned with water or mushroom liquid if too strong; add perhaps a drop of sesame and/or chile oil.
Some people like to add a little crushed garlic, minced green onion, and/or gingerroot.