Tip the carrots into a heatproof bowl. Pour the vinegar into a small pan with 3 tbsp water and the honey or sugar. Add a pinch of salt, bring to the boil, then immediately pour this over the carrots and leave to pickle while you prepare the rest of the dish, stirring occasionally.
Cook the noodles following pack instructions until tender, then drain, rinse under cold running water and drain again. Alternatively, if you prefer warm noodles, cook them at the end just before serving, without rinsing afterwards.
Heat the sunflower oil in a small pan over a medium heat. Tip the red pepper flakes, cumin, chilli flakes and a large pinch of salt into a small heatproof bowl. When the oil is shimmering (be careful not to let it smoke), carefully pour it over the spice mixture in the bowl, stirring to coat everything in the oil. Set aside.
Return the pan to a medium-low heat and toast the sunflower seeds for 3-5 mins until just turning golden. Remove from the heat. Mix the tahini and a pinch of salt with 5-6 tbsp water in a small bowl until smooth and pourable. Set aside.
Put the tofu in a shallow bowl or on a plate, break it apart slightly and spoon over the soy sauce and the chilli oil you made in step 3.
Divide the noodles between serving bowls and top with the tahini sauce, cabbage, pickled carrots, tofu, toasted sunflower seeds, herbs and spring onions. Drizzle over the carrot pickling liquid and serve.