How can I reset my iPad if I have forgotten the restrictions passcode?

You should be able to reset it back to factory defaults by connecting it to your computer's iTunes, you may have to use recovery mode : http://support.apple.com/en-gb/HT201263

Or if you have Settings > iCloud > Find My iPad enabled on it you could try logging into your account via http://www.icloud.com and sending a remote wipe message to it