Bring water to boil in a large pot, turn off the heat, add the vermicelli, cover and leave to cook for 5-7 minutes, rinse under cold water and drain in a sieve. Set aside.
In a wok or pan, heat sesame oil and quickly fry minced ginger and garlic with some sugar for a minute or two taking care not to burn. Add the lamb and stir fry on high heat till browned and semi cooked.
Now toss in the spinach and red chillies and fry for a further 7 minutes till cooked but not soggy. Add soy, vinegar and cook for a minute more before mixing in the vermicelli. Check the seasoning and finally sprinkle the sesame seeds over the filling.
Spoon this filling into lettuce leaves (shape into rolls if you want) and serve with wasabi-soy.