Dissolve the yeast in 1/2 cup warm water and stir. Place 3 cups of the flour in a bowl with the salt and olive oil. Add the yeast mixture and stir. Slowly add enough water to create a dough that sticks together and isn't too wet. Dump the dough onto a lightly floured surface, and using as much of the additional flour as needed begin to knead the dough with your hands until it is smooth, soft, but no longer sticky. Place the dough in a lightly oiled bowl, cover with plastic wrap and let sit in a warm spot in your kitchen until it has doubled in size, about an hour and a half.
While the dough is rising, mix together your topping ingredients in a bowl and set aside. Once the dough has doubled, preheat your oven to 400 degrees F. Lightly oil a 13 X 9 inch baking sheet and dump the dough into the prepared pan. Use your fingers to press the dough evenly into the pan, and create dimples all across the top with your fingers. Spoon the topping mix evenly across the top of the focaccia and let sit for 10 minutes. Bake the focaccia for about 25 minutes, or until it is crisp and lightly golden brown on top. Let cool for 10 minutes and then cut into fingers using a serrated bread knife. Serve warm or at room temperature.