Place the pork shoulder in your slow cooker or Dutch oven, seasoning it lightly with salt and pepper if desired.
Cover and cook on low for about 8 hours, or until the meat is fall-apart tender and easily shreddable with forks.
Once cooked, remove the pork from the cooker and let it cool slightly to handle. Use forks or tongs to shred the meat into juicy, stringy pieces, mixing in crispy bits of bark for added texture.
Warm the buns slightly in a preheated oven or toaster oven until soft and fragrant—that gentle heat helps enhance their softness and aroma.
In a small saucepan, lightly caramelize sliced onions over medium heat until golden brown and sweet, or prepare raw if you prefer crunch and sharpness.
Spread a generous layer of smoky BBQ sauce over the toasted buns, then pile on the shredded pork, pressing down gently to pack the filling.
Add slices of bright pickles, caramelized onions, and a spoonful of coleslaw on top of the meat, layering flavors and textures.
Cap with the top bun, pressing down just enough to hold everything together without squishing out the sides.
Repeat the process with remaining buns and fillings, then serve immediately for the best crunch and juiciness.
If making ahead, store the shredded pork separately in an airtight container and reheat gently before assembling the sliders just before serving.