Slice tofu into 6 planks, then cube into ¾–1" pieces. Leave cubes undisturbed on the cutting board to prevent breakage.
Bring 2–3 quarts water to a boil in a wok or pot. Salt generously. Gently slide tofu into the water using a bench scraper. Simmer 2 minutes. Remove with a slotted spoon and transfer to a paper towel–lined plate to dry.
Prep the aromatics: grate ginger, press garlic, slice scallions (light parts only), and chiles. Grind Sichuan peppercorns in a mortar and pestle or crush with a pan.
Heat dry wok over high heat. Add oil and ground beef. Break up and brown for ~2 minutes.
Add toban djan. Stir-fry 30 seconds.
Add gochugaru and ground Sichuan peppercorns. Stir-fry 1 minute.
Add scallions, chiles, garlic, and ginger. Stir-fry ~90 seconds until softened.
Deglaze with Shaoxing wine, scraping up browned bits. Reduce ~30 seconds. Add stock, soy sauce, salt, sugar, MSG, and sesame oil. Bring to a boil.
Gently fold in tofu. Simmer 2 minutes.
Stir cornstarch and water together into a slurry. Add to wok and stir gently until sauce thickens to a stirrable, saucy consistency. Add more stock if too thick.
Serve over rice and garnish with scallion greens