Is there a way to repair a players inventory/hand without giving the player access to the /repair command? Something that could be used if an admin needed to repair a players inventory for example.

Maybe create a [repair] sign and break it after?

http://wiki.mc-ess.net/wiki/Sign_Tutorial#Repair_Sign

You can't. You have to create this sign in game.

How can i do that in console? I also want to use it for vote party rewards.