Coat a large saucepan with oil, add the red pepper flakes and toast over medium heat until aromatic. Add the chicken broth and 28 ounces (2 cans) water and bring to a light boil. Add the soy sauce, dark soy sauce, Worcestershire and rice wine, reduce the heat and simmer for a few minutes. Remove from the heat and let cool to room temperature. Add about 3 to 4 ladles of room temperature sauce to a resealable plastic bag and add the chicken. Let marinate for at least 1 hour.
Add the cornstarch to the remaining sauce and mix well.
Heat a large skillet or a flat top grill to medium-high heat. Remove the chicken from the marinade and discard the marinade. Cook the chicken in the hot skillet until cooked through and lightly browned. Add the remaining sauce mixture and cook to desired consistency, coating the chicken well. Transfer to a serving bowl or platter.
Mix the onions and cilantro together in a bowl.
Assembly: Warm the tortillas. Fill with Kung Pao Chicken and top with the onion/cilantro garnish and chopped peanuts.
Recipe courtesy of Dominic Lau, co-owner of Don Chow Tacos in Los Angeles, CA.