Place the soy sauce, sesame oil, rice vinegar, garlic, ginger, chilli and lime juice into a blender and blitz until smooth. Pour over the mushrooms and leave to marinate for 10 minutes.
Smack the cucumber a few times with a rolling pin then chop, place in a bowl and sprinkle with salt. Mix together all the other ingredients. When the cucumber has been sitting for about 10 minutes then drain and pour over the dressing. Serve with extra chilli slices and sesame seeds sprinkled over.
Heat a skillet over a high heat until searing hot then add the mushrooms and cook until browned and caramelised. Steam the bao buns according to package instructions. Serve the mushroom filling, bao buns and cucumber with chopped spring onions, chilli and sesame seeds.
Notes
Note on nutrition information: The displayed is for the filling and the salad, you will need to add on the information for the bao buns depending on which ones you buy