For the Teriyaki Sauce:

1. In a bowl, whisk together soy sauce, water, garlic, ginger, sesame oil, rice wine vinegar, honey, and red pepper flakes. Set aside.

For the Chicken and Veggies:

1. Heat 1 tbsp olive oil in a large skillet over medium-high heat. Add onion and bell peppers, cooking until softened and slightly browned (about 7 to 9 minutes). Transfer to a bowl and set aside.
2. While the veggies cook, pound the chicken with a tenderizer and dredge in flour until evenly coated.
3. In the same skillet, add the remaining 2 tbsp olive oil and add the chicken. Cook for about 5 minutes, turning until golden brown on both sides and nearly cooked through.
4. Pour in the prepared teriyaki sauce and scrape up the brown bits from the pan. Bring to a boil and let it simmer for a couple of minutes until the sauce thickens.
5. Add the veggies back to the pan, reducing the heat to low. Cook until the chicken is completely done (no longer pink in the middle).
6. Garnish with fresh cilantro (optional) and serve over brown rice or whole-grain ramen noodles.