Pour the rice into a pan, add the water and place on the heat. When starting to boil, reduce the heat, cover with the lid and simmer until the liquid is absorbed. Remove from the heat and set aside for 10-15 minutes.
In the meantime, mix the rice vinegar with the sugar and add salt. Pour over the rice and mix with a fork. Allow to cool completely.
Put one nori sheet on the bamboo mat and cover with a damp tea towel to let it cool.
Cover with ¼ of the rice on half of the nori along the length, leaving a 2 cm margin on the borders, compressing with the palm of your hand. Lay one thin slice of the smoked salmon along the length of the rice in a strip.
Wash the cucumber, opened it in half and remove the seeds with a spoon. Cut thin cucumber slices lengthwise. Wash the celery stalks and cut them in thin slices.
Put a few thin slices of cucumber and celery over the central part of the rice strip. Drizzle lime juice and season with freshly ground pepper. Roll the nori tightly with the help of the bamboo mat, and squeeze to seal when you reach the end. Repeat with the remaining nori sheets.
Keep in the fridge until serving.
With a very sharp knife, cut in sections of about 2.5 cm each and serve with soy sauce served in a bowl.