Heat a wok until smoking. Add the vegetable oil and, when hot, add the minced pork and stir-fry until browned. Then add the garlic, spring onions and bean paste and stir-fry until fragrant. Add the stock, shaoxing, soy sauces, sugar and salt. Bring to the boil, add the tofu and reduce the heat to a gentle simmer, allowing the liquid to thicken slightly. Add the Sichuan pepper and sesame oil and gently mix together.