On iOS, "Reset Home Screen Layout" auto-arranges your application icons. Is there an equivalent for this on my Nexus 7 Android tablet? Right now my icons across several screens.
Go to Settings->Apps, swipe to All, scroll and press Launcher, then select Clear data.
Your home screen is as good as new :)
UPDATE: As suggested by Chahk below, a good way to avoid cluttering your homescreen is by going to the Play Store then going to Menu -> Settings and un-checking the Auto-add widgets option.
On newer devices/OS versions (i.e. Nexus 5X), try going into Google App instead of Launcher, select Storage, Manage Space, CLEAR LAUNCHER DATA.