1-Pour 1 1/2 cups water, orange juice, lemon juice, rice vinegar, and soy sauce into a saucepan and set over medium-high heat. Stir in the orange zest, brown sugar, ginger, garlic, chopped onion, and red pepper flakes. Bring to a boil. Remove from heat, and cool 10 to 15 minutes.
2-Place the chicken pieces into a resealable plastic bag. When contents of saucepan have cooled, pour 1 cup of sauce into bag. Reserve the remaining sauce. Seal the bag, and refrigerate at least 2 hours.
3-In another resealable plastic bag, mix the flour, salt, and pepper. Add the marinated chicken pieces, seal the bag, and shake to coat.
4-Heat the olive oil in a large skillet over medium heat. Place chicken into the skillet, and brown on both sides. Drain on a plate lined with paper towels, and cover with aluminum foil.
5-Wipe out the skillet, and add the sauce. Bring to a boil over medium-high heat. Mix together the cornstarch and 2 tablespoons water; stir into the sauce. Reduce heat to medium low, add the chicken pieces, and simmer, about 5 minutes, stirring occasionally.