In a bowl combine the olive oil, rosemary, garlic and yeast. Add the water to dissolve the yeast. Add the flour and salt. Mix and knead by hand until you have a smooth ball of dough. Spread the cornmeal on a flat surface. Place the dough on the cornmeal and cover with a warm, damp dish towel. Allow the dough to rise until double in size, for about 50 minutes.
With a rolling pin, flatten the dough into a round and cut it into 6 equal wedges. Flatten each wedge with your fingers, pounding it out very thin. Spread on the baking sheets and bake until golden brown, for about 10 minutes. Brush each piece of flatbread with remaining extra-virgin olive oil and sprinkle lightly with kosher salt.
This recipe yields 6 flatbreads.