Right now, AFAIK, the only way to know if someone WANTS a critique is by clicking the avatar and viewing its page to check for the "Please critique this style!" text.

Two different possibilities:
1) A "critique me" icon or symbol of some sort: an icon that's shown near the avatar's title (or somewhere easily visible from any of the pages that show multiple avatars (ex: the newest uploads page).
AND/OR
2) Checking the "ask for comment critiques" box automatically adds a tag called "critique" or "critique me." However this suggestion would/will be more useful if search by something other than popularity was/is implemented.
![sooo >:]](./images/smilies/tardmotes2/happyfaic.gif)