Warm the almond milk in a small bowl in the microwave. (Do not heat too much, as it will kill the yeast.) Add maple syrup and the yeast. Stir and let rest for 15 minutes, while the yeast activates.
Meanwhile, combine the brown rice flour, tapioca starch, arrowroot flour, xanthan gum and salt in a large bowl. Whisk to combine. Pour in the yeast mixture and the melted coconut oil. Mix everything together and keep mixing for 3 minutes.
Move the dough to a floured surface and knead for 2 minutes. If the dough is sticky, dust your hands with a little tapioca flour.
Roll the dough into a ball and place it in a coconut-oiled bowl for an hour. Cover with a dish-cloth. The dough should double in size.
When the hour is almost up, bring a large pot filled with 10 cups of water and the baking soda to a boil. Meanwhile, transfer the dough to a cutting board and cut it into 8 equal pieces. Roll each piece out to 15-18 inch logs. If the dough seems dry and is cracking, wet your hands a little while rolling it out. Shape each log into a U shape and twist one side over the other. Press down gently to secure the pretzel shape.
One by one, gently lower each pretzel into the baking soda bath and boil for 30 seconds at a time. Remove and place on a parchment lined baking sheet.
Let the pretzels rest for 10 minutes while you preheat the oven to 450F.
Sprinkle the pretzels with coarse salt and bake for 15-20 minutes, until golden-brown.
Serve with delicious homemade mustard!