Numbers is a native application on iPad and will open Excel files seamlessly (there may be font differences), you can manipulate the files in Numbers, you can edit them and you can save them as either Numbers or export to Excel if you want to transfer them back to a Windows machine,
in addition, from the Windows machine you could either print the cut list as a .pdf and send that to yourself, or you could screenshot and send that. I would think of those two choices the .pdf would be most reliable.
In addition to this info if you have an app like Google Drive you can load on your computer and on the pad it makes the transfer from machine to machine pretty painless. Once Drive is signed in on both machines anything loaded into it will show up on the other to download pretty quick.