Put noodles into big pot of boiling water. Cover, turn heat off, and let it sit for 10 minutes.
Chop cilantro and mint together, set aside.
Peel and seed cucumbers, cut into match sticks and set aside.
Peel carrot, then use vegetable peeler to ribbon the rest of the carrot. Set aside.
Rinse bean sprouts with cold water, allow to drain well. Set aside.
Chop chicken breasts into small chunks.
Measure oil into large frying pan, add chicken, and brown on all sides.
Add coconut milk, curry powder, and crushed chilis. Stir well, cover, and let it simmer for 10 minutes or until chicken is cooked through and sauce is quite thick. Remove from heat.
As the chicken is simmering:
Once noodles have been sitting for about 10 minutes, drain and rinse with cold water. Divide between 2 large bowls.
Divide lettuce between bowls. Place a mound of bean sprouts off to one side of the lettuce on each plate.
Divide cilanto/mint mixture, cucumber, and carrot among servings, and arrange in sections on top of each.
Add cooked chicken to each bowl, sprinkle chopped peanuts over each serving, and serve with fish sauce.