Rub the salmon with salt and sugar. Let stand for a while at room temperature.
Prepare the noodles according to the instructions on the package. Pour from the water into a colander and rinse with cold water. Put back in the bowl.
Stir in a little oil and some salt and stir.
Cut the salmon piece, no further down than it holds together. Put it in a hot pan with butter and fry until it gets a little color. Then flip over and fry briefly on the other side so that it becomes a raw core.
Mix noodles with mango, cucumber, sliced green onion and thinly sliced red pepper fruit without kernels.
Save some for decoration. Put on a platter and serve immediately.