Things you'll need to "skinnify" a tie:
1) An iron and ironing board
2) fabric glue
Step 1: Split open the tie
Use scissors to remove the strip(s) of fabric on the back that are used to tuck the tail of tie into. Then use scissors to split open the back of the tie.
Since a single strand of thread holds the whole tie together, once you snip that strand, you should be able to pull it out without continuing to cut it, but this takes some practice. If you need to, just cut the thread as you go.
Split the tie all the way up to the skinny part.