Preheat the oven to 350°F. Line a sheet pan with parchment paper and set aside.
In a large bowl, whisk together the almond flour, tapioca flour, flaxseed, salt, garlic powder, and baking soda until evenly combined. Add the sweet potato puree and mix with a spatula until a very thick, uniform dough forms. The dough should be soft and thick but not sticky. If it is still sticky, add more tapioca flour a tablespoon at a time and mix it in until it is no longer sticky.
Sprinkle a clean surface with tapioca flour. Place the dough on top of the flour and sprinkle with more tapioca flour. Roll the dough with a tapioca-floured rolling pin into a ⅛-inch-thick 12 × 10½-inch rectangle. Use your hands to create an even rectangular shape, adding pieces of dough where needed and flattening with your rolling pin.
Use a pizza cutter or knife to cut the rectangle into about fifty-six 1½ × 1½-inch squares. Carefully transfer them to the sheet pan, leaving space between them.
Bake until golden and crisp, 16 to 20 minutes. Sprinkle with salt and let cool completely in the pan on the counter before serving or storing.
