Dice the chilli peppers as finely as you can for both the dipping sauce and the garnish for the tofu. I like to remove the seeds for both presentation and to cool down the chillies a little.
Dice the single spring onion for the dipping sauce as finely as you can.
Slice the remaining 3 spring onions into rings at a 45° angle and set them aside.
Finely dice the garlic clove.
Place the diced chilli for the dipping sauce, the minced garlic and finely diced spring onion in a bowl with the dark soy sauce, rice vinegar and sesame oil, then give it a good stir.
Have a taste of the dipping sauce and add sugar to taste. Start with one teaspoon first, then add more after as required.
Heat a wok over a high heat and when it is hot, add the Szechuan peppercorns and toast them for 60 seconds, keeping them moving all of the time. Then transfer them to a grinder or pestle and mortar and finely crush them.
Combine the cornflour with the salt, pepper, Szechuan pepper, and Chinese five-spice on a flat plate and mix well.
Cut the tofu into 2cm (¾") cubes and then pat them dry on some kitchen paper.
Heat some oil (3-4cm or 1¼-1½" deep) in a wok until it reaches 170°C or 340°F.
Place the tofu on the plate with the cornflour mix and roll to coat.
Fry the tofu in the oil in two batches. Move the tofu constantly and cook each batch for 90 seconds or until golden.Drain any excess oil on kitchen paper before serving.
Serve sprinkled with the sliced spring onion and the remaining diced chilli pepper.