Whisk together the gluten free flour, xanthan gum, and salt in a large bowl. Pour in the boiling water and stir with a spatula until a shaggy dough forms. Once cool enough to handle, knead the dough briefly on a floured surface for 1 to 2 minutes until smooth. Cover with a damp towel and let rest for 15 minutes.
Whisk together the tamari, rice vinegar, sesame oil, sriracha, and sugar in a small bowl until the sugar dissolves. Set the dipping sauce aside.
Divide the dough into 4 equal portions. Roll out each piece into a thin circle about 7 to 8 inches across. Brush the surface with sesame oil, then scatter a generous layer of sliced scallions and a pinch of flaky sea salt over the top.
Starting from one edge, roll the circle up tightly into a log, then coil the log into a spiral like a snail shell, tucking the end underneath. Flatten the coil gently with your palm, then roll it out again into a circle about 6 inches wide. Repeat with the remaining dough portions.
Heat about 1 tablespoon of avocado oil in a nonstick skillet over medium heat. Place one pancake in the skillet and cook for 2 to 3 minutes per side, pressing down gently with a spatula, until both sides are golden brown and crispy.
Repeat with the remaining pancakes, adding more oil to the pan as needed. Cut each pancake into wedges and serve hot with the dipping sauce on the side.