Coat a large, nonstick pan with cooking spray. Heat 2 teaspoons oil in pan. Add cauliflower rice, onions, and red bell peppers. Stir-fry over medium-high heat, for about 5-6 minutes, until cauliflower rice is soft. Stir in chicken, warmed sauce, and continue to stir-fry for 2-3 minutes until entire dish is hot. Sprinkle in scallions and mix well.