How to Make It
In a small bowl, combine the soy sauce, vinegar, chili-bean paste and scallions.
With a small melon baller, hollow out the tofu cubes and reserve the balls. Put the tofu balls in a large bowl and add the remaining ingredients. Using your hands, mix thoroughly. Carefully stuff each tofu cube with 1 level tablespoon of the filling, mounding it.
Fill a wok or a very large skillet with 2 inches of water and bring to a boil. Arrange the dumplings in a double-tiered bamboo steamer; set the steamer over the boiling water. Cover and steam until the filling is firm and cooked through, about 10 minutes. Serve the dumplings with the sauce.