Put the thinly sliced chillies and water in a pestle and mortar and grind until a puree.
Next make up the sauce, mix all the ingredients for the sauce in a small bowl and set aside.
Heat the oil in a large frying pan or wok and fry the chicken until cooked, this may need to be done in batches. Remove and set aside.
Using the same pan (no need to clean as you will get more flavour), add the garlic paste and chilli paste and fry for 1min. Add the tomatoes and fry for a min.
Return the chicken to the pan and stir ensuring the chicken is fully coated in the chilli sauce.
Add the noodles, the sauce, spring onions and bean sprouts and mix well.
Check the seasoning and serve immediately with crispy shallots and shop bought prawn crackers.