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 for 90 seconds until softened.
Deglaze with Shaoxing wine, scraping up browned bits. Reduce for about 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