1. Combine hoisin, vinegar, ginger, and 3 tablespoons water in a bowl; set aside. Place bean threads in a separate bowl; cover with boiling water, and let stand 10 minutes or until tender. Drain.
2. Dredge the pork in cornstarch. In a large nonstick skillet, heat 1 tablespoon oil over medium-high heat. Working in 2 batches, sauté pork 2 minutes per side or until golden brown and just cooked through. Remove with slotted spoon. Add remaining oil, then add bell pepper, carrot, peas, and garlic. Cook, stirring frequently, about 2–3 minutes or until vegetables are crisp-tender. Add reserved hoisin mixture to the pan; bring to a boil. Add pork, and cook 1 minute or just until pork is heated through.
3. Place the bean threads on a platter, and top with the stir-fry. Garnish with cilantro leaves, if desired.