Chiles, hoisin, Chinese aromatics, and citrus zest create a bold flavor base for this crispy chicken, which tastes like it’s straight from your favorite takeout spot. Cornstarch not only forms the chicken’s light crust, but also thickens the spicy, sweet-and-sour sauce into a sticky glaze.
Chicken: Slice chicken into bite-sized pieces and season with salt. In a zip-top bag, add cornstarch, followed by the chicken. Close the bag and shake to coat chicken pieces evenly; then set aside. (This can be done several hours ahead and up to overnight; the longer the chicken is in the cornstarch, the thicker the crust.)
Sauce: Into a bowl, add hoisin sauce, vinegar, sugar, soy sauce, fish sauce, tomato paste, and chile-garlic sauce. Stir to combine. Set aside.
Chinese mirepoix: Thinly slice scallions on the bias, using the white and pale green sections, and just a bit of the dark green. (Reserve remaining scallion greens for another use.) Set aside ¼ of the sliced scallions for garnish. Peel, then smash garlic with the flat side of a knife, and coarsely chop. Scrape off ginger skin using a spoon, then grate using a Microplane.
Heat oil in a wok over medium-high heat. Meanwhile, cut the yellow pepper: remove the white inner ribs and discard; cut the rest of the pepper into a large dice. Check oil temperature with a wooden chopstick: it should bubble immediately. Remove chicken from the bag, shaking off excess cornstarch, and carefully place into the hot oil in a single layer. Let fry undisturbed until cooked through and very crisp for a total of 4-5 minutes, flipping halfway through. Meanwhile, zest the orange and lemon.
When chicken is cooked and crispy, remove with a slotted spoon and drain on a paper towel-lined plate. Pour off and discard all but 2 tablespoons oil; rinse out and dry the pan. Reheat remaining oil over medium-high heat. Add dried chiles and sauté until they darken and begin to smoke, about 1 minute. Add scallions, ginger, and garlic, and stir to combine. Add yellow peppers and cook 1 minute, tossing to combine, then add the sauce. Stir and cook 1 more minute, adding 1–2 tablespoons water as needed if the sauce is too thick. Add chicken and toss to coat and combine. Finally, shower with lemon and orange zest and give the contents a final stir. Taste for seasoning.
Assembly: Place rice in a bowl. Spoon chicken and sauce over rice, including a good mix of vegetables and chiles along with the chicken. Garnish with reserved sliced scallions, and serve immediately.