Place pork in the bottom of a 3 qt crock pot. Layer peppers and garlic over the pork.
In a small bowl mix teriyaki sauce and rice vinegar. Pour over the ingredients in the crock pot.
Cook for 3-4 hours on high heat or 7-8 hours on low heat.
A half hour before you are ready to eat, bring water and rice to a boil in a medium saucepan. Reduce heat to medium-low and simmer, covered 20-25 minutes, until the liquid has been absorbed and the rice is tender. Let rice stand, off of the heat, covered, for 5 minutes before serving.
While the rice is cooking, remove the pork from the crock pot and shred it using two forks.
Mix the peanut butter in with the sauce in the crock pot, until the sauce is smooth. Return the shredded pork to the sauce in the crock pot and keep warm over low heat while you prepare your rice.
Serve pork over the rice, topped with peanuts and green onions, if desired.