Cook rice according to package directions in a large pot with 1 1/2 cup water; put aside.
Broccoli florets should be placed in a steamer or colander over a pan of boiling water. Set aside after steaming for 5 minutes, or until cooked through and vivid green.
In a small bowl, whisk together chicken stock, orange marmalade, orange juice, soy sauce, vinegar, ginger, garlic, Sriracha, if using, and 1 tablespoon cornstarch.
Sprinkle the remaining 3 1/2 teaspoons cornstarch equally over the chicken and season with 1/2 teaspoon salt and 1/2 teaspoon pepper.
Heat canola oil in a large skillet over medium high heat. Working in two batches, add chicken and cook until golden brown, about 6-8 In a large skillet, heat the canola oil over medium-high heat. Working in two batches, add the chicken and cook for 6-8 minutes, or until golden brown. Stir in the chicken stock mixture for about 2-3 minutes, or until it thickens. Sesame seeds are added last.
Serve the chicken with rice and broccoli as soon as possible, garnished with green onions if prefered.