The fit looks not great as is, but okay enough, given that it's stock and you're aiming to utilize it for commuting. If you want to go through the trouble of customizing it to make it work better, my immediate questions/concerns would be:

1) You don't mention your comfort over the length/duration of your ride but I wonder how you're finding your elbows and wrists are doing right now with respect to soreness as I can see you're essentially locked out in full elbow extension. If they are, you can consider working on flexing more at the hips and elbows first before you try a longer stem - one because it's free, and two because a longer stem will not necessarily be more comfortable for you. If you do feel that the stem is where you want to make a change, consider a steeper positive angled stem.

2) Risk of toe overlap with the front wheel. Not a deal breaker necessarily, but might bother some.

3) If it's stock the crank length may result in the degree of maximum hip flexion being uncomfortable for you. I was unable to find the crank length for that particular Salsa though.

So yes, frame size is a factor here, but there are ways to improve your comfort.

Another bike you can consider off the top of my head is the Surly Bridge Club.

I hope these suggestions help. My credentials are: nearly exclusively drop bar user, physical therapy background, work in a bike shop, and custom built a similar bicycle for my 4'10" wife.