In a bowl combine orange juice, soy sauce, vinegar, cornstarch, orange zest, garlic, ginger, red chili flakes, brown sugar, and salt. Whisk it until the sugar dissolves and keep the sauce mixture aside.
⅓ cup fresh orange juice, 1 tbsp soy sauce, ¼ cup rice vinegar, ½ tbsp cornstarch, ½ orange, 3 clove fresh garlic, 1 tbsp fresh ginger, ½ tsp red pepper flakes, 3 tbsp brown sugar, salt