The magic of this easy recipe starts with cooked chickpeas. I first soaked the chickpeas overnight to get rid of the the anti-nutrients such as phytic acid and to make them more digestible.
The #1 crispy tip is drain really well, then dry really well. The less moist the chickpeas are, the crispier they will become. Its proven.
Once your chickpeas are dry, peel the skins. It can be tedious and annoying, but in my experience, it does help them crisp up a bit more in the oven. And when it comes to crisping chickpeas, every little bit helps!
Next step is to bake at 425 F (218 C) for 45-50 minutes. In experimenting, I found that, at too high a temperature, the chickpeas burn quickly while being tender in the center. And if too low, no crisping seems to happen for a very long time. Every oven is different so experience with yours. So 425 degrees is the sweet spot.
Let the chickpeas cool once out of the oven, and store without a sealed lid. Doing so lets the chickpeas breathe and stay crispy longer than just 1 day.