You can delete an iPad app similar to how you would move the icon for an iPad app. First, tap and hold the icon until all of the icons on the screen are jiggling. This is the "move state" from the Moving Apps tutorial. When in this state, some of the icons will have a black circle at the top with an "x" in the middle.
Simply tap the "x" button to delete an app. Don't worry about accidentally deleting an app. The iPad will confirm your choice before the app is actually deleted.
What about apps that do not have an "x" button?
You are not allowed to delete the default applications that came installed on your iPad. These include the Calender, Contacts, iTunes, App Store, Game Center, etc. You can remove some of these applications by enabling parental controls on your iPad. Find out how to enable parental controls.