Yh, you simply drag an application to trash to remove it from your computer.
The only file/s that are left on your mac that are associated with that application are preferences files which do not slow down your mac, they merely take up disk space (only a few KB's). Sometimes an application may also leave behind cache files, however these files do not slow down your mac either, they just take up disk space.
If you do want to delete everything associated with a certain application just drag it to the trash and then search the applications name in spotlight. Delete the results that are associated with the application that you just moved to the trash.
However as mentioned before applications that install via an installer will require an uninstaller to uninstall fully. Uninstallers are located in the applications folder. So for example to uninstall Photoshop, look for a photoshop folder in the applications folder and in that folder there should be an uninstaller and an application as well. To uninstall just launch the uninstaller