Whisk whole wheat flour, rye flour, salt and yeast together in the bowl of a stand mixer. Set aside.
In a seperate bowl, combine honey, melted butter, buttermilk and egg. Add wet ingredients to dry ingredients.
Using the dough hook attachment, mix on low until mixture is just combined. Increase speed to medium and knead dough for 3-4 minutes, adding the scallions during the final minute of kneading. The dough will clear the sides and bottom of the bowl and be slightly tacky to the touch. Remove bowl from the mixer and cover with plastic wrap. Let the dough rise for about an hour.
Remove dough from the bowl and divide into 8 equal pieces. Cover with plastic wrap. Working with one piece of dough at a time, shape into a ball and then, using a rolling pin, roll into a thin round, about ⅛ inch thick.
Heat 1 tablespoon of canola oil in a large skillet, preferably cast iron, over medium heat. With the help of a metal dough scaper, carefully remove dough round from the work surface and transfer to the skillet. Cook until spotty brown and cooked through, about one minute on each side. Transfer to a wire rack and brush with melted butter. Sprinkle with sea salt flakes if desired. Reduce heat to medium low and continue with remaining pieces of dough, adding more oil as necessary to keep a thin layer on the bottom of the skillet. Serve immediately or freeze.