Hey @the3dstig. Ring does not directly sell these extra adhesive for the setup of the Alarm Devices, but the are the Command 3M Double Sided Sticky Tape. I personally recommend using the Velcro version of this brand as that it makes it easier to take the sensors and any other Alarm Devices down from their install location whenever you need to!
Hi @AngelaC! It does depend how you installed it, as you may have used the Doubled Sided Sticky Tape, or you may have used screws into the wall. The best trick when removing the sensors when mounted with screws is to go up and over when trying to take it out of the screw. For the adhesive setup, I recommend using a butter knife to help wedge in between the stinky tape and the wall, but it should be able to be peeled off. Hope this helps! 