As far as I recall, you need to delete your twitter account from your iPad. (it won't delete your account from twitter, just from the iPad) That's the only way to remove it.
If you still want to tweet but have more control, you can use a third party app (I use tweetlogix but there are others)
that app will maintain the separation and you have more control over what it accesses.
Welcome to Apple Support Communities. We're all users here.
There are (at least) two explicit permissions you may have given TO Twitter to make iOS apps more Twitter-friendly on your iPad, depending upon your device.
Have you revoked access to them?
To check, open your browser on another device, log in to Twitter and go to https://twitter.com/settings/applications, then, if necessary, revoke access as shown below.
NOTE: This is the Mac Safari view of the Twitter page linked above. The iPad I use is on iOS 5, so your permissions screen might look different. I have another non-Twitter permission blanked from the top of this screenshot