Sprinkle the pork with salt and pepper. Sear
the pork shoulder
in a pan on medium-high heat.
Combine the chicken stock, fish sauce and chiles in a stockpot. Bring to a gentle simmer. Add the pork, cover and braise until tender, 2 to 3 hours.
Shred the pork and grill over medium-high heat.
Add the pork to the buns. Top with kimchi and avocado slices.