In Return of the Jedi, the Emperor's throne room contains these clusters of what appear to computer panels. What is the purpose of these? How can they be accessed?
These are described as "Duty Posts" in the Star Wars: Inside the Worlds - Complete Locations factbook. Apparently they lift up to allow access from underneath.
The Wookieepedia article on Command Sector Duty Posts contains a wealth of detail about their operation, all copied almost verbatim from the Haynes Death Star Manual (which itself seems to have been cribbed from the earlier Death Star Technical Manual, created as a supplement to the Star Wars: RPG)
On the Death Stars, those who man the stations have a rank of lieutenant or higher, and two to four can be stationed at any time. These served as a "mini bridge" for the commanding officer(s) in question. They were extendible at the base to allow access to the assigned commanding officer(s).
The duty posts were surrounded by eight control boards, four of which were dedicated to the particular tasks assigned to the post, and the remainder handled communications, damage and diagnostics, computer access, as well as a direct feed to the post's computer access. Within the post was a ventilated base. The eight boards specific functions included two duty monitor modules, two command interface modules, one computer access module, one communications module, one secondary computer access module, and one damage control module. On the duty monitor module were several instruments, including a security lockdown lever. The computer access module possessed several instruments, including two viewscreen buttons. The communications module contained several instruments, including process state indicators and a secure comlink. The command interface module contained several instruments including a command authority verifier. Lastly, all of the modules have red blinking lights on the exterior edge of the module that acted as module status indicators.
Control Panels for workstations no longer in use. You would stand in the center, turn to each view screen and either monitor or activate doors/lifts/etc. There is no one there because of the impending confrontation, or maybe the controls are no longer in use, but they were at one time controlling something. One of those panels will slide to the side to allow someone to enter. Look at the star destroyers or other control panels in different ships. Nothing is exactly like this, but there are some control stations that do look like these.