Trying to move, modify, or delete a resource pack zip file after minecraft has loaded it results in a "This action can't be completed because the folder is open in Java(TM) Platform SE binary."
1. Get a resource pack in the zip format.
2. Select it in the resource packs menu.
3. Select Default
4. Try to delete the resource pack.
After selecting the resource pack, you have to close minecraft in order to delete it. Does not apply to resource packs in a folder.