Scenario: I boot into Recovery mode and open Disk Utility. Then I select the primary hard drive and choose 1 partition. Will that destroy the recovery partition as well?
No destruction will happen - This repartitioning you propose is possible to safely do.
The recovery partition won't modify itself (since it's in use) and will survive attempts to erase itself when it's in charge.
You also can resize things in general when booted from the main OS as long as files that are stored in the area being trimmed are mobile and not in-use or locked.
You have to enable a debug mode for Disk Utility to see and work on the Recovery HD so it's planned to be something you have to know a trick and go out of your way to tamper with. (Note: Debug mode is removed in 10.11 with the redesigned Disk Utility app)