Combine the water and yeast and allow the mixture to activate (approx. 10-15 mins). Combine the buckwheat flour, salt and olive oil and add the yeast mixture. Work slowly to make a dough, cover and allow to rise in a warm spot for 1 hour.
Divide the dough into six pieces. Take one piece, shape into a flat disc and place between two sheets of baking paper. Carefully roll out the dough into a round pita shape approx. 1/4 inch thick. Pierce the dough with a fork a few times and dust lightly with polenta.
Heat up your 10" cast iron pan and brush with olive oil. Cook the pita for a few mins on one side until puffy and repeat on the other side.
Fill them up with your desired meat and vegetables and serve immediately. Alternatively, you may put them into the fridge wrapped in foil and they can be reheated the next day in the oven.