Find My iPad is an invaluable feature that let's you remotely locate your iPad if it is lost or stolen. It also allows you to send a sound, in case it is just lost in your house somewhere, lock it or erase its content altogether.
To do this, you must first have the service turned on on your iPad. If it is, go to iCloud.com on your computer or another device, log in with your AppleID and click on Find My iPhone. Now you can select which device to find. Once it is located it will be displayed on a map and you have three options: Play Sound, Lost Mode and Erase iPad. Play Sound is helpful for finding an iPad that is nearby (within earshot). Lost Mode will lock the iPad so nobody can get into your information. If that doesn't ease your mind enough, Erase iPad will clear out everything. You can restore from backup if you eventually find it.