Halve cayenne pepper lengthwise, remove the seeds and finely slice the flesh. Finely slice the garlic. Slice the lemongrass into 4 cm chunks Place in a shallow bowl and add 2 tablespoons of soy sauce. Slice the chicken into 2 cm chunks. Add to the bowl and stir. Leave the meat to marinate until use.
Meanwhile, slice the broccoli into small florets. Slice the cucumber into strips.
Cook the rice noodles according to the instructions on the package.
Heat 1 tablespoon of sesame oil in a wok. Stir-fry the chicken with the marinade in approx. 5 minutes until golden brown and cooked. Remove the meat from the wok. Remove the lemongrass (it is very tough).
Heat the rest of the sesame oil in the wok and stir fry the broccoli on a high heat for 4 minutes. Add the cucumber and the rest of the soy sauce. Stir fry for another 2 minutes.
Serve the rice noodles, chicken and vegetables in 4 bowls.