Put the smoked flour in a pot, place the salmon on top of it on a steaming insert or metal sieve and put the pot on the stove. WARNING: Do not open the lid during the smoking process! Smoke for about 5 minutes on low heat and then open the lid, preferably in the open air. Peel the potatoes and boil them in salted water until they are soft. Mix them with ricotta and butter until they are firm and creamy, add a little salt. Cut the nori leaves in half and spread the potato mixture on top. Cut the smoked salmon into strips and place them alternately with the caviar in the middle of the potato mixture. Roll up the nori sheets with the mixture and cut into small maki pieces. For the salad, cut the cucumbers into noodles with a julienne peeler, season with wasabi, sesame oil and fish sauce. Arrange the salad in a circle on the plate with the help of a dressing ring and serve the potato maki on top.