In a small bowl combine the teriyaki sauce, orange peel, orange juice, 1 teaspoon of the sesame oil and the fresh ginger.
Prepare 4 large pieces of heavy foil (about 17x15-inches each). Fold up the edges of each piece a few times to contain the ingredients when added.
Rinse the tilapia filets and pat dry with clean paper towels. Place one filet in the center of each piece of foil. Top each fish filet with one-fourth of the frozen vegetables and one-fourth of the sauce mixture.
To make packets, bring the foil sides up over the top of the ingredients and double fold. Double fold both ends to seal.
Gently stack the packets into a 5- to 6-quart slow cooker. Cover and cook on low-heat setting for 6 hours.
Meanwhile cook the rice vermicelli noodles according to package directions. Drain and toss with the remaining 1 teaspoon sesame oil.
Remove packets from the slow cooker using long handled tongs. Open packets carefully to avoid the escaping steam. Fish should be opaque and flake easily with a fork when done.
Serve fish, sauce and vegetables over the vermicelli noodles. Sprinkle with toasted sesame seeds, if desired.