I Accidentally Deleted the Launcher
You can find a launcher on the Google Play Store and remotely install it that way. Then reboot the phone after it installs. Once the phone reboots it should prompt you to pick a launcher and then you can go from there. 

So for instance if you want the Google Launcher.

Then click on the Install button and select the device. As long as the device is online and signed into your account, it will install for you automatically.

Edit. Forgot to say this. You can do this from another device, just have to do it through the browser and not the app. Or since you said Windows 8.1 I assume thats a desktop/laptop. You can do it on there as well.

Edit 2. Adding on what @Izzy commented. You can download the apk for google's launcher from here. Then sideload via adb, using the command adb install &lt;/folder/nameof.apk&gt;.