I recently saw by a Friday night dinner that the challah bread was dipped in salt a few times. Is there a specific amount of times to dip it, and why dip it in the first place?
Great question. I myself have had this question and looked it up, and I found the article Why Do We Dip the Challah Bread in Salt? to be very interesting.
To sum up what's written there:
It's dipped in salt every time bread is eaten, and not only shabbos, the reason being your table is compared to an altar, which the sacrifices brought on the altar all had salt, so too your bread should.
It is done because the bread is referred as kindness in kabbalah, and salt on the other hand is revered as severity, and we want to overpower the kindness over the severity.
It is done three times, the reason is based from kabbalah as well, bread is לחם which is the numerical value of 78, the name of g-d is 26, times 26 x 3= 78 (26 being the value of the name, and 3 is the 3 times we dip), to remind us we don't only live from the bread we eat, but also the blessing of g-d in our food.