AEmbarrassed to ask but … what exactly is an Avast skin? Is it an essential or just a cosmetic feature?
A cosmetic feature, not just a change of color, more like artwork, and many choices. 
Don’t be that, there is no such thing that dumb questions!
So…just ask!
The only dumb or embarrassing thing would be NOT to ask a question when you don’t know what the answer is.
If you’re using the Home (free) version, well, skins are necessary.
You can only by-pass them using ashSimp2.exe from avast folder
But, why would you by-pass some great piece of art? ;D