Whisk together vinegar, soy sauce, sesame oil, marmalade, brown sugar, salt, and pepper in a small bowl. Set aside.
Cut chicken into small pieces, and toss into a large zip-lock bag along with the corn starch; shake to coat.
Add oil to a large skillet and heat over medium-high. Once hot (oil will shimmer) add chicken. Brown on all sides and then toss into slow cooker. Pour the vinegar mixture over the chicken; stir, cover, and cook on low for 4-5 hours.
Cook rice as directed on package. Cover and set aside.
Dice pepper and zucchini and sauté in a large skillet over medium-low heat until tender. Season with salt and pepper.
Serve chicken over rice, with veggies and orange wedges on the side.