Once the dough has at least doubled in size, punch the top of the dough to remove all the air bubbles. Then, place the dough on a clean work surface.
Gently stretch the dough into a rough rectangle shape. With a bench scraper or serrated knife, cut the dough into 12 equal pieces. Each should be about 90g.
Pull the corners of the dough towards the center, flip, and then roll each piece of dough into a round, tight ball. Repeat until all the rolls are shaped.
Allow the rolls to rest for at least 10 minutes. This allow the gluten to relax, making it easier to roll out the sourdough hot dog buns with a rolling pin.
Taking one dough ball at a time, roll out the dough into a 5-in wide by 8-in long rectangle. You want to roll it out nice and thin, until it is about 1/8th of an inch thick. Lightly dust the dough with flour if it is sticking to the rolling pin.
Starting with the edge closest to you, roll the dough TIGHTLY, like a cinnamon roll, to form a cylinder. Pinch the edges and seams to seal, the gently roll the dough to help further seal the seams. Place each hot dog bun on a parchment paper lined baking sheet, about 2 inches apart. Not ready to bake these in the same day? No worries! Cover the shaped bun with plastic wrap and store them in the fridge overnight. A few hours before you're ready to bake the buns, pull them out of the fridge and allow them to rise. This will take longer, since the dough is cold from the fridge.
Once shaped, cover the shaped buns with this plastic cover or plastic wrap, and let the dough rest for its second rise. In my 70 degree F kitchen, the second rise took about 1-2 hours. The rise times greatly depend on the temperature of your kitchen. You will know the final proof is complete when the hot dog buns have grown and look puffy.