1. In a medium bowl, combine the soy sauce, rice vinegar, honey, ginger, garlic, and red chili flakes. Add the chicken pieces, ensuring they are well-coated. Let them marinate for at least 30 minutes in the refrigerator.
2. Heat the vegetable oil in a large skillet over medium heat. Once hot, add the marinated chicken pieces without overcrowding the pan. Cook for about 5-7 minutes until the chicken is cooked through and lightly browned.
3. Remove the chicken from the skillet and set aside. In the same skillet, add the diced mangoes. Cook for about 3-4 minutes until they start to soften and release their juices.
4. Return the chicken to the skillet with the mangoes. Stir to combine and cook for an additional 3 minutes, allowing the flavors to meld together.
5. Season with salt and pepper to taste. If you desire more heat, feel free to sprinkle additional chili flakes.
6. Garnish with chopped cilantro before serving, and enjoy the dish over a bed of jasmine rice.

A little tip from my kitchen to yours: if you want to make the sauce thicker, you can mash a few mango pieces against the side of the skillet as they cook. It thickens the sauce while enhancing the mango flavor.