In a large pot over medium-high heat, bring 3 quarts (2.8 l) water and the salt to a boil and reduce the heat to a low simmer. Cut the tofu into 1-inch (24-m) chunks, slip them in the water, and gently simmer for 10 minutes. Line a plate with paper towels and, using a slotted spoon, transfer the tofu to the paper towels to drain. Meanwhile, in a large skillet or wok over low heat, toast the peppercorns and dried red Chinese chiles, shaking the skillet or wok occasionally, until fragrant and beginning to color, 3 to 7 minutes. Transfer to a plate and let cool. Transfer the cooled peppercorns and chiles to a spice grinder and process to a coarse powder.
In the same skillet or wok over high heat, add the oil and the chile pepper along with the anchovies, if using. Cook for a minute or two and then add the garlic, ginger, and pork and fry until the pork is browned, about 4 minutes.
Stir in the black beans, doubanjiang, sugar, and ground pepper and chiles. Cook for a few minutes, stirring often, to let the flavors meld.
Add the chicken stock and sesame oil and bring to a boil. Stir in about 3/4 of the cornstarch-water mixture and let the sauce boil, stirring continuously, until it thickens, which should take just a few minutes. You want the sauce to resemble a glossy gravy that will cling to the noodles. If you think it needs to be a little thicker, simply add a little more of the remaining cornstarch slurry.
Taste the sauce and, if desired, adjust with more Worcestershire and/or soy sauces. Carefully stir the tofu into the sauce, using a gentle pushing motion with the back of your spatula and shaking the pan to coat the tofu without it crumbling into pieces.
Set a large pot of water over high heat, bring to a boil, and cook the noodles until al dente. Drain well and divvy the noodles among 4 bowls. Top with the hot tofu mixture and garnish with the cilantro, sesame seeds, and sansho.