If you want to uninstall Peakto Search for Lightroom, you'll have to disable the plugin in Lightroom and remove the application.

You can follow these steps: 

1) in Lightroom,  disable the Peakto Search Plugin

Launch Lightroom and choose File > Plugin Manager

- 1 - find the plugin in the list

- 2 - click on disable

2) Quit Lightroom, Quit Peakto Search and remove `Peakto Search` application from your Application folder.

(Trash it and empty the trash)

3) Now, if you want, you can clean the Lightroom Plugin folder

With the finder, use the "Go to Folder command" and paste the following path: 

~/Library/Application Support/Adobe/Lightroom/Modules

You can trash the peakto-plugin-for-lightroom file