Whisk together warm water, sugar and yeast. Set aside for 10-15 minutes to activate.
In a large mixing bowl, stir together 4 cups of flour and salt.
Add the melted vegan butter and yeast mixture (once activated) to the flour. Mix until a ball forms, then knead for 5-7 minutes, by hand or using a stand mixer with the hook attachment. Add flour, as necessary, so that the dough does not feel too sticky (it should still be a soft dough).
Lightly oil a bowl. Form the dough into a ball, place it into the bowl and roll it around to cover in oil.
Place a wet towel over the bowl. Let sit for one hour (ball should approximately double in size).
Once the dough has risen, preheat the oven to 425°F and prepare a baking sheet by lining with parchment paper.
Place the dough onto a lightly floured surface. Roll out the dough to a large rectangle that is ~1/2 inch thick. Cut into ~3/4" x 1" pieces.
Boil the 3 quarts of water in a large pot. Once it's boiling, carefully add the baking soda (the water will rise quickly, so do this slowly and carefully).
In small batches, add the pretzel bites to the boiling water. Boil for ~1 minute, then flip over and boil for another minute. Remove and place on prepared baking sheet. Continue until all the pieces have been boiled.
Brush each with melted vegan butter or oil and top with pretzel salt.
Bake in the preheated oven for 10-12 minutes, until golden-brown.