Heat oil in a large skillet over medium-high heat and brown pork for 5 minutes, turning. Transfer to a 4-quart slow cooker.
Add vinegar, soy sauce, 1/3 cup water, garlic, bay leaves and pepper. Cover and cook on low for about 6 hours until the pork is fork-tender and reaches at least 145°F.
During the final hour, bring rice and 1 1/2 cups water to a boil in a covered saucepan, reduce to low and cook for 40 to 45 minutes, then rest covered for 10 minutes.
Lift pork to a plate and remove bay leaves. Pour cooking liquid into a small saucepan, skim excess surface fat and simmer for 5 to 8 minutes until reduced to about 3/4 cup; return pork to the sauce.
Steam cabbage in a covered steamer over simmering water for 8 to 10 minutes until tender.
Divide pork, sauce, rice and cabbage among 4 plates, allowing cooked pork to rest at least 3 minutes before eating.