Prepare the frozen crispy chicken strips according to package directions (air fry ~11–12 minutes recommended). Let cool until warm, then cut into bite-sized pieces and place in a large bowl.
Heat a medium pot over medium-high heat and add 2 tablespoons toasted sesame oil. When the oil shimmers, add the minced garlic, ginger paste, and red pepper flakes and cook, stirring constantly, for about 30 seconds.
Add the light brown sugar and granulated sugar to the pot and stir to moisten. Add the orange juice (from 1–2 large oranges) and 1–2 teaspoons orange zest if using, then stir until the sugar dissolves.
Stir in the white vinegar and soy sauce, mixing to combine.
Whisk the cornstarch with 1/4 cup water in a small bowl until smooth, then pour into the sauce and stir. Cook the sauce, stirring, until it thickens to a syrup-like consistency.
Taste and adjust seasoning: add more red pepper flakes for heat or a pinch of salt if needed.
Pour as much sauce as desired over the cut chicken in the large bowl. Drizzle the remaining 2 teaspoons toasted sesame oil over the coated chicken and gently toss to combine.
Serve immediately over cooked rice if using, and garnish as desired.
