Combine in a large bowl the flours, salt and bicarbonate (you can also use a kitchen machine). Add water and oil and knead for 5 minutes to get an homogeneous dough, then let it rest in the fridge for one hour.
Divide the dough into 5 equal parts then shape them into balls. Using a rolling pin, roll out dough pieces into 7-inch rounds, about 1/8-inch in thickness, on a lightly floured surface.
Heat a nonstick pan and cook each flatbread for a few minutes on each side, when you start seeing toasted brown spots all over it then it's done.
Stuff the flatbreads and eat right away, or let them cool down and keep in a plastic bag in the fridge for 5-6 days or up to 1 month in the freezer and heat them on a hot pan before serving.