In a small bowl, whisk together orange juice, vinegar, ginger, and scallions; set aside.
Spray a medium skillet with nonstick cooking spray and heat over medium heat. Add red pepper, carrots, cabbage, celery, and onions; add orange juice mixture and cook, stirring, until pepper slices are slightly tender. Remove from heat and set aside.
Place rice in a bowl and top with vegetable mixture. Add salmon and garnish with sesame seeds. Serve.