In a large mixing bowl, stir together the water, yeast, and sugar. Let the mixture sit for 5 minutes, undisturbed, or until it's started to foam on top.
Stir in the flour, butter, and salt. Mix until evenly combined. Knead the dough, about 5 minutes, until it's soft and pliable. The dough should be sticky, but not enough so that it's impossible to remove from your fingers. Add more flour only if needed.
Lightly oil a large mixing bowl. Add the dough to the bowl, cover, and let rise for an hour in a warm place- or until doubled in size.
In a large pot, stir together the water and baking soda and bring the mixture to a rolling boil. In the meantime, punch down the dough and transfer it to a lightly floured counter top. Divide the dough into 8-10 equal pieces.
Roll each piece of dough out into a long rope, a little under 2' long. Beginning at one end, wrap the dough tightly around the hot dog, pinching the ends to seal it together. Place the wrapped hot dog on a lightly oiled sheet or parchment paper on a baking pan. Repeat until all the hot dogs are wrapped.
Working in batches of 2-3, add the dogs to the boiling water and let them cook for 30 seconds. Remove them with a slotted spoon and return them to the pan. Repeat until all dogs have been boiled.
Brush them with melted butter and sprinkle salt over top. Bake the pretzel dogs at 450 degrees for 12-14 minutes, or until the dough's a dark golden brown. Let the pretzel dogs rest for 5 minutes before serving with your favorite sauce.