Combine all the ingredients for the steamed buns in the bowl of a stand mixer outfitted with the dough hook. Mix at the lowest possible speed for 10 minutes.

Lightly oil a medium mixing bowl and put the dough in it. Cover the bowl with a dry kitchen towel. Place in a warmish place. Allow the dough to rise until it doubles in bulk, around 1 hour, 15 minutes.

Punch the dough down and turn it out onto a clean work surface. Divide the dough in half, then divide the half into 5 equal pieces. Roll the pieces into logs, then cut each log into 5 equal pieces, making 50 pieces total.

Roll each piece into a ball. Cover the dough balls with plastic wrap and allow them to rest and rise for 30 minutes.

Cut out fifty 8 cm squares of parchment paper. Coat a chopstick with the fat.

Flatten out one ball with the palm of your hand, then roll it out into an 8 cm long oval. Lay the greased chopstick across the middle of the oval and fold the oval over to form the bun shape. Place the bun on a square of parchment paper.

Let the buns rest for 30 to 45 minutes; they will rise a little.

Set up a steamer on the stove. Steam the buns on the parchment squares for 10 minutes. Remove the parchment paper.

For the crispy pork belly, place the pork belly, salt, garlic, and onion in a large pot and cover with water. Bring to a simmer and cook for 1 ½ hours until the pork is tender.

Remove from the pot and allow the pork to cool. Place the pork on a plate and keep uncovered in the refrigerator for at least 3 hours.

Heat a deep fat fryer to the lowest setting and fry the pork for 20 minutes. Remove, cool, and refrigerate for at least 3 hours.

For the final cooking, heat the deep fat fryer to its highest setting, fry the pork again for 10 minutes until the skin crisps up. Remove, drain, and slice for the pork buns.

For the pickled cucumbers, slice 2 cucumbers thinly, add 1 tablespoon sugar and 1 teaspoon salt. Let sit for 5 to 10 minutes before using.

To assemble, open the bun and spread some hoisin sauce. Add the cucumbers, then layer with the crispy pork belly, and top with the spring onions. Serve with sriracha sauce on the side.