GrowAPair saidOr you could quit being worried about a "tiny layer of fat."
HAHAHA! seriously your stomach looks fine.
However, (not that I know anything about your workouts) work all parts of your core. And when I say core I don't mean hundreds of crunches. The core is a large section of your body that you should work all parts of to develop your abs. You need to work everything - abs, obliques, transverse (cum gutters as I like to call them), hip flexors, abductors, adductors, lower back, upper part of the glutes.
Have you tried pilates? That work out is all about the muscles i just listed.
Also if you increase your lower body workouts, and do them correctly, usually core will follow suit.
And don't do the same core exercises every day. Change them up.
Get a book called "The new rules of lifting for abs" lots of great stuff on how to focus your workout on developing your core muscles.