Put a pot of water on to the stove to boil for your noodles.
In a wok over medium-high, heat the cooking oil and fry the finely diced shallots until soft and translucent for a minute or so, add the finely chopped garlic and fry for a minute until fragrant, then add the grated ginger, combine and fry for 30 seconds or so, then reduce the heat to medium.
Add the sesame oil, Chinese sesame paste, chilli oil, natural crunchy peanut butter, fish sauce, and optional tamarind sauce if you're using it, and stir to combine well, as the peanut butter breaks down and softens and a sauce forms. Taste and adjust to your palate. Turn the heat to low or, if the sauce has thickened right up, turn the heat off completely.
To the pot of boiling water, add the noodles and cook until al dente – better to be slightly under-done – then drain the noodles. If you want to loosen up the peanut sauce, stir through more sesame oil or a little water, turn the heat on again to heat up the sauce, then transfer the noodles to the wok while still hot, stirring in the spicy peanut sauce, taking care not to break the noodles.
Distribute the sauce-covered noodles to bowls, drizzle on a little red chilli oil, and garnish as you like with sliced red chillies, pan-roasted peanuts, crispy fried shallots, and fresh coriander leaves. Serve with lightly stir-fried Asian greens such as bok choy on the side and serve immediately.