Make sure your phone is recognized with adb by typing adb devices
Then run the following code. It basically mounts the system drive and then you move the apps to a backup file where they are there if you later change your mind, but they will no longer run.
To be fair I totally stole these commands from here
and then added Twitter and amazon mp3 store to itsu mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /system cd /system/app mv Facebook.apk Facebook.bak mv com.amazon.mp3.apk com.amazon.mp3.bak mv Twitter.apk Twitter.bak mount -o ro,remount -t yaffs2 /dev/block/mtdblock3 /system sync
down with facebook.............