A Wonderfully Entertaining Sushi Video

is kept outside the restaurant to purify the place, ward off bad spirits and enhance the prosperity of the establishment. The act shown here is parody, you're not supposed to touch that salt (who would want to, after having it outside for days or weeks?)
Salt is "shio" in Japanese and thrown by the handful as a ritual by sumo contestants just before the bout.
Salt has other purifying uses around the Japanese hosehold, e.g after a nasty encounter with a landlord or real estate, "shio" may be called for to clean the air.

As for me very interesting video. especially for me - I have never eaten sushi

holy shiz! This is so awesome! It needs to be put to music, with the Japanese track left in place. I love it.