I'm sure this is a dumb question, but...

I'm sure there is a SYW (show your work) subforum that applies to short stories. On AW, I believe there is a 50 post rule where you must make 50 posts before submitting anything for critique.

I'd suggest finding the right subforum and taking a look at stories posted, if you feel inclined, offer critiques until you reach that mark

Sydneyd is correct. There is a Share Your Work forum, and you need to have 50 posts here before you are eligible to post work for critique there.

caw

There are a variety of critiquing sites, and at least one is good (critters.org). You might just look around until you find a place that seems reasonable.