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No sorry, you cannot remotley delete the messages from the iPad.
The only option you have is to remotley wipe the iPad which will delete everything from it and return to new, so a bit extreme but would included deleting the messages.
To do this, from your computer
Go to www.iCloud.com/#find
enter your Apple ID > click Find My iPhone.
Click on the option All Devices > chose the device you want to erase.
Click Erase iPhone/iPad.
And everything on the iPad will then be deleted and it would need to be set up again like when you first received it.
If you would like any additional information or assistance, please do not hesitate to let me know.
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