The short answer is, you cannot. I find it weird why Google did not include this option. The Nexus 7 home screen by default is set to 5 and I really have no need for so many screens.
Considering there are folders to help manage your apps, this option should never have been excluded unless Google did this on purpose to force users to spread out all app icons on the home screen then that would make folders have no use at all.
So anyway, if you really want to remove the other home screens, the only solution is to download some other launcher like Apex or Nova.
There are free versions of them and you can already manage the home screens with it. There is no need to purchase the pro or paid version in order to be able to manage home screens.
Back then, I blogged about how good the LG Optimus One is. Really … Android did them a favor because it resulted in a cool smartphone that rivals that of the iPhone. There is soft-touch coating all around the phone, interrupted only by the four nice, clickable Android buttons below the 3.2″ screen, the 3 megapixel camera on the back and the chrome-like bezel.
LG’s additions to the software actually make this phone more attractive with the big additions coming with a launcher, some nice widgets and added DivX VOD support to the operating system as well as subtle touches to the user interface of the dialer and contacts. There is no Adobe Flash support in the browser, and ThinkFree Office is included.
But the core of how good the LG Optimus One is, is how it works seamlessly with Android’s applications like Goggles to identify photos like landmarks, books, structures and many more. Look. To see is to believe right? Check out the video below detailing what things to expect when one owns an LG Optimus One.