If you do not have the Android SDK Installed:
http://developer.android.com/sdk/index.html
Then download ES File Explorer from here:
https://dl.dropbox.com/u/54456659/ES%20File%20Explorer_1.6.2.1.apk
If I understand you correctly, you are able to use the Kindle, correct?
Be sure you have Root Permissions:
http://xdaforums.com/showthread.php?t=2069117
If you can not access the Kindle directly, use onemeila method.
Perform the above download directly from your Kindle using Silk , Opera or Dolphin.
Once the download has completed, choose "Open" to install.
Complete the install of ES File Explorer, then Open ES File Explorer directly
after the install or through the Kindles /Apps/
Once ES File Explorer is open, the go to the Settings, choose Root
Settings. Check every box. Then you will be presented with a Superuser
dialog box. Be sure to click on Allow. Then go back to the main ES File
Explorer Screen. You will notice at the top, it shows where you are in
the file system. By default ES File Explorer open to /sdcard/ so
You need to click UP. This will place you at the Root / - next
Click on the System folder, next the App folder. Long press
whatever file you would like to delete and choose "Delete" or
"Move" to Move the file to another location. Just FYI you
will find that most of the programs reside in /data/apps.
I suspect Next Launcher is in the /data/apps folder.
If none of this works, PM us, we will get you back online.
We offer free phone support to everyone in the XDA
Community.