Hi Lovepeaceguru,
You should be able to just open the folder you have set as your 'Incoming Files Folder' on WinMX and there you can delete the OpenNap incompletes or even just move them to a separate folder for later if you prefer. I dont have any of my opennap incompletes to look at, but I dont remember them being 'marked' in any special way in this folder, so you may have to load them and make notes as to which are opennap and which are not then go and delete the ones you want gone from the folder itself...