1. Enclose the bread
An easy way is to trap the bread's own steam while it's baking. Some options:
- Wrap or otherwise enclose the bread in foil while baking.
- Place the bread on a cookie sheet. Place a metal pot, upturned, over it so that it is completely enclosed. Further enhance this by placing the bread on a piece of tin foil, then on a rack or grill (or anything that will keep it off the hot surface), before covering with the upside down pot.
- Place the bread inside the pot and seal the top with foil. Again, if you can keep it from touching the bottom of the pot, you can get an even thinner crust.
Bake the bread while enclosed, and then for the last 5 minutes, remove the pot and let it bake uncovered.
The first stage (enclosed) will give you a bread with virtually no crust, and then in the second stage (not enclosed), a thin crispy crust will form.
Note that this crispy crust will not last long in any kind of humidity! Re-heat to dry it out again if you want to eat it crispy.
2. Freeze the bread
Another way is to let your bread rise to the point a little before it should be baked (depends on side of bread). Place it in the freezer in a freezer bag. Once frozen, wrap it in foil and bake it directly. Don't thaw it. You'll achieve the same effect—zero crust, then bake another 5 minutes to get a nice crispy crust.
If you want a very fancy crispy crust that cracks and sings coming out of the oven, you will need to use fancier techniques or get a steam injection oven. Lots of people achieve this without a steam injection oven, however. I recommend www.thefreshloaf.com as a spot to read from / talk with people who are really into this and have thought of all kinds of crazy ways to get maximum crispiness out of their crusts. Check out Txfarmer's bread here. She doesn't use any special oven and still gets amazing results, probably by placing bricks/oven stones in the oven, and enclosing the bread somewhat as I describe above.