Who advised you to reinstall? If you go the App Store and tap on the purchased tab at the bottom - if the app shows up in there - in the "not on this iPad" section - you can tap the cloud icon to install it again - as long as you use the same Apple ID.
However, just because it "vanished" from your screen does not mean that it isn't on another screen. Did you swipe from screen to screen to look for it? Or did you use the search feature on the iPad? Swipe to the right from your first home screen to get to the search.
To delete An app - tap and hold down on the icon until it wiggles then tap the X that pops up. Tap the home button when you are done.