Using baking powder to make baked food crispy The recipe I use for chicken wings achieves a fried texture by dusting the wings with baking powder and then baking at $220^\circ\pu C$ ($425^\circ \pu F$). The chicken is also dusted with salt and other seasonings, but I assume they're not chemically relevant.  What chemical process is going on, here?

I'd assumed it was some kind of reaction between the baking powder and the skin of the chicken, though I had no idea what. Then, one time, there was a stray boneless, skinless chicken thigh in with the wings I bought, and that also became crispy on the outside when cooked this way. I've also heard of people using the same technique on oven fries.
Not exactly an academic source, but a few articles on Serious Eats suggest that baking powder's gas releasing reaction forms small bubbles of protein on the surface that add surface area that can quickly dehydrate (a prerequisite for crispiness) and solidify. 
It's also a pretty common ingredient in things like batter for fried chicken, where I imagine the expanding bubbles do a similar thing—allow easier removal of water from the batter by increasing the surface area so it can crisp up.

The pH change may also help break down the skin, if applied in advance.