I actually can't take full credit. My girlfriend, who works part-time for a local sourdough baker, provided the recipe, method, and (at least) half the labor.
The dough is really simple--it's basically identical to Tartine country bread dough, except that we transferred it directly to well-oiled sheet trays after bulk fermentation.
We used about 1 kg of dough per sheet tray. Stretching it out to the corners of the trays took a while...we did it gently and incrementally over the course of almost an hour, giving it plenty of time to rest and rise a bit whenever it tightened up. It's relatively easy to tear it at this stage if you try to rush things, but we probably took more time than we needed just because we had plenty of other work to do.
You can dress it however you like. The ones in the photos are topped with quartered figs, sliced red onions, rosemary, and goat cheese. The figs, onions, and rosemary were baked together with some olive oil and balsamic vinegar beforehand, and the goat cheese was added after baking. We also did some with pesto, halved cherry tomatoes (face up), and parmesan.
Baking time is going to vary a bit depending on how you top it and how crispy you want it to be. In general, we baked at 450 for ten minutes, rotated the tray, and then continued baking until it looked done--usually about another ten minutes. If it still isn't crispy enough for you at that point, you can remove it from the tray and bake directly on the rack for another couple of minutes.