In a large mixing bowl, whisk together the buckwheat flour, tapioca starch, water, and salt. Cover with plastic film and let it rest for at least 1 hour. I usually prepare the batter the day before and let it rest overnight in the refrigerator. Make sure to give it a good whisk before using, as the flour tends to fall in the bottom of the bowl.
Prepare the leeks: halve the leeks lengthwise and slice them crosswise into chunks. Wash and drain them.
Heat a tablespoon of oil in a large skillet over medium heat. Once hot, add the leeks and sauté for 3 minutes. Pour in the white wine, add the thyme, salt, and pepper. Lower the heat to low and cover with a lid. Cook on low for about 35-40 minutes, or until the leeks are very soft. Taste and adjust seasonings if needed. Cover to keep warm.
Heat a teaspoon of oil in a large non-stick skillet over medium heat. Use a paper kitchen towel to grease the skillet and remove excess oil.
Once the skillet is hot, pour about 1/3 cup of the buckwheat crepe batter and tilt the skillet in a circular motion to spread evenly into a thin layer. Cook for about 30-40 seconds, or until the top of the crepe appears dry and the edges are golden brown. There is no need to flip the crepe.
While the crepe is still in the skillet arrange about 1/2 cup of the leek fondue in the center and fold the edges to enclose the filling. Slide the crepe to a serving plate, top with coconut bacon, and optionally (but recommended) a dollop of hummus with a drizzle of sesame oil on top. Repeat with the remaining crepe batter. Serve immediately.
Notes
For more flavor, I like to caramelize the leeks. Once they are cooked and soft, bring the heat to high and let them caramelize for 3-5 minutes, stirring regularly to make sure they don't burn.