Place the water in the bowl of a stand mixer. Add the sugar and 2 teaspoons of kosher salt and whisk to combine. Sprinkle the yeast over the the water mixture evenly and let stand 5-10 minutes until foamy.
Fit the mixer with the dough hook, then add the flour and butter to the water mixture, stirring by hand with a rubber scraper until most of the flour is incorporated. Turn the mixer on low, and mix until just combined, then increase the speed to medium and knead the dough about 5 minutes, or until the dough pulls away from the sides of the bowl. Turn out the dough into a bowl greased with canola oil and cover. Place in a warm spot and let rise about 1 hour, or until doubled in size.
Preheat the oven to 450 degrees F, and lightly oil parchment paper for (2) baking sheets and set aside.
Turn the dough out onto a counter -- do not sprinkle flour on the surface -- and gently deflate. Divide the dough into 8 equal pieces, cover, and let rest 10 minutes to relax the gluten. Using your hands, roll each of the 8 pieces into 7" long logs. and place on the prepared baking sheets, cover, and let rest 30 minutes.
Place the water in an 8 quart pot and bring to a boil. Add the baking soda -- it will fizz up! Reduce the heat slightly and add the pretzels, only a few at a time, and boil 30 seconds per side. Remove from the water with a slotted spoon or spatula, and place back on the baking sheets. Repeat with the remaining pretzels, then brush each one lightly with egg wash and cut 3 diagonal slits with a serrated knife in each one, being careful not to cut down more than 1/4".
Sprinkle with pretzel or coarse sea salt, if using, and bake in the middle and upper third of the oven for 10-13 minutes, rotating the pans halfway through the baking time. When the pretzels are a deep brown color, remove from the oven and cool on a wire rack.
Slice the buns and serve with your favorite hot dogs. Enjoy!