In a small bowl stir together the brown sugar, smoked paprika, salt, onion powder, garlic powder, black pepper and cumin.
Sprinkle pork on all sides with spice mixture.
Heat the olive oil in a large Dutch oven until hot but not smoking. Sear pork on all sides, working in batches in necessary.
Pour the stewed tomatoes and beer over the pork. Add the Worcestershire, onions and garlic. Reduce heat to a low simmer. Add a lid at a vent and allow to cook until pork is very tender and falling off the bone, about 4 hours. Shred using two forks, removing the bones from the pot. Remove meat from the pot with a slotted spoon to drain off excess moisture.
To make the sauce, whisk together the yogurt, lemon juice, dill and red onion. Chill until ready to serve.
Split the burger buns and fill with pork, top with cucumber, tomatoes and yogurt sauce.