In a mixing bowl, combine orange juice, orange zest, rice vinegar, soy sauce, brown sugar, ginger, and red pepper flakes.
Place chicken thighs directly into the sauce. Let marinate in the fridge for 2 hours.
Heat a skillet over medium-high heat. Pour your chicken and all of the sauce directly into the hot skillet.
Let this bubble and cook until the chicken reaches an internal temperature of 165 degrees, 15-20 minutes. Flip the chicken every 5 minutes to let it cook evenly. The sauce will reduce as it cooks.