Heat a wok or large sauté pan over medium heat. Add the ginger, garlic and the whites of the green onions and sauté for about 30 seconds. Add the pork and season with salt and pepper.
Cook, stirring occasionally and using a wooden spoon to break apart the pork, until the pork is browned about 6 minutes. Add the soy sauce and cook for an additional minute. Use a slotted spoon to remove the pork to a medium mixing bowl.
In a small bowl stir together the sriracha and hoisin. Add the hoisin mixture to the pork and stir to combine. Stir in the remaining green onions and set aside.
Spoon the pork filling into the bao buns and garnish with the cucumber, green onions and cilantro. Serve immediately.