The temp files you see are the files that EAC is currently working on.
You can set EAC to rip the files in one long string (one after the other) and compress with a background program (e.g. Lame command line). As it compresses each file it renames it with a random name and then goes to work on it. When finished it renames the MP3 file back to its correct name and deletes the WAV file.
If you close EAC before its fully finished then you get left with the WAV files and the random named file as well. The encoding would have only partly happened.
If you are sure the files you have with random names are not wanted (try playing them) then delete them but ALWAYS check at the bottom of EAC to make sure all copression has finished before closing EAC or you will find you get more of these random files and you will be missing a few tracks from your audio rip.