How do I get crispy but thin bread crust?
Assuming that this is what you want: 




This kind of crust is made with steam injection. Normal household baking methods will give you a thick crust, which is usually also hard. Wetting and covering it right out of the oven will give you a chewy crust. If you bake the bread in a fitting pan and tweak the recipe, you can get thin, almost non-existant crust, but also soft, like sandwich bread. 

For what you see in the picture, you need standard French bread dough (60% hydration, AP flour) and a blast of steam in the oven at the beginning of baking. Sadly, homemade steam methods which rely on evaporation won't work, because there is a limit to the amount of water which will evaporate even of high temperatures, and you need to get more steam inside than that. So, you'll either need a pro oven or a steam modding (which only works on an oven with vents, unless you are prepared to drill a hole into the oven cavity). 

For extra tweaking the crust, you can use a glaze. We had a question explaining the different glazes and their results.