Mix the water and the dry yeast in a small bowl and stir well. Set aside.
Combine the buckwheat flour, spelt flour, charcoal and some fresh ground pepper in a large mixing bowl. Using a wooden spatula, stir them well until you have a uniform dark color and make a well.
Gradually add the water and knead for 2 to 5 minutes until the dough forms a ball (first using the wooden spatula then using your hands). Add more flour if it's very sticky to your hands.
Divide the ball into 2 medium pizza (or 6 small). Rub each dough with olive oil, put them back into the bowl and cover the bowl with a kitchen towel. Set aside for 1 to 2 hours to prove.
Prepare a silicone baking mat (or a piece of baking paper) and flour it. Flatten the dough with the palm of your hand first. Then roll the dough with a rolling pin. Move regularly the sides of the dough and flip it sometimes too to be sure that it doesn't stick to the mat and add more flour when needed. Create 2 medium pizza round (or 6 small pizza).
Preheat the oven to 180-185 °C (fan).