What do you call these type of desks? They are extremely long and they are fixed, I am thinking they must have a name since they're so different from regular desks. Is it the case? If not, what words would you use to refer or describe them?
There is no conversational word for this other than "table" or "desk".
If you work in the business of selling this kind of furniture, or you're looking to buy such furniture, then you'll find listings under such categories as "university fixed seating", "tiered seating", "table systems", or some other jargon term you would only need to know if you had to deal with it all the time.