In a large mixing bowl or stand mixer, add coconut oil, ground flax, sugar, white vinegar and warm water. (This melts the coconut oil and sugar while allowing the flax seed to soften and bloom.) Allow it to stand until the water has cooled enough to touch but is still warm.
Once the mixture is cooled slightly so that it will not kill the yeast, add the yeast and gently mix.
Add the gluten-free flour, and then add the salt. (Do not add salt against the yeast without adding the flour or else the salt can also inhibit yeast growth.) Mix for 2 minutes on medium speed to fully incorporate all ingredients.
Cover the bowl and allow the dough to rest for 10 minutes.
Generously spray your bread pan with coconut oil.
Lightly dust your counter with more gluten-free flour. Gently coax the dough out of your bowl. Use a dough scraper if necessary. Dust the top of the bread dough. Using your hands, you can roll or shape the dough into a flat rectangle. Make sure it does not stick to your countertop. If it does, you can add additional flour to your surface.
Loosely roll the dough into a log and place it in your prepared loaf pan. Loosely cover the bread dough and allow it to rise in a warm place for approximately an hour, or until the dough has crowned 1/2" above the pan at the center of the loaf.
Make a swift 1/4" deep cut across the length of the bread dough with a sharp blade. Brush the loaf with coconut oil to promote browning if desired.
Bake your gluten-free bread for 55-60 minutes or until the center reaches approximately 210F.
Carefully turn out the bread onto a cooling rack. (If you leave it in the loaf pan to cool, it will turn out gummy.) Do not cut until bread is completely cooled.