Well I guess I could have spent more than 30 seconds trying to do this before posting that question. I just got it off really easily so I'll share what I did. I'll leave the question open for a few days in case someone else has a better approach.
I took a wooden BBQ skewer and slipped it under the rim tape at the valve opening:
Then used that to lever the tape up just enough to slip a dispoable wooden chopstick under it in the same position:
The chopstick, being stronger, allowed me to lever the tape up enough to jam another one in crosswise, straddling the rim walls:
Then I was able to pull the first chopstick back out and put in in parallel to the second one so they were both straddling the rim walls and I could start sliding them apart:
Then it was just a matter of sliding one of the chopsticks about 6" along the rim so I could grab some of the rim tape between them and pop it over the rim wall:
At that point I just pulled it a little more and the whole loop popped off.
Hope this helps others.