In a small bowl, whisk together the rice wine vinegar, lime juice, fish sauce, honey, and a pinch of salt until well combined. Set aside.
Place the sliced cucumber and red onion in a large bowl. Add the red chili pepper, if using.
Pour the dressing over the cucumber mixture and toss gently to coat evenly. Let it marinate at room temperature for 10–15 minutes.
Just before serving, sprinkle the chopped cilantro and crushed peanuts over the salad, toss gently, and adjust seasoning if needed. Refrigerate if not serving immediately.
In a mixing bowl, whisk together the brown sugar, reduced-sodium soy sauce, rice wine vinegar, lime juice, and fish sauce. Set aside.
Prepare the rice noodles according to the package directions.
While the noodles cook, heat the olive oil in a wok or sauté pan over medium-high heat. Add the chicken and sauté until cooked through, about 6 minutes. (Cook to an internal temperature of 165°F (74°C).) Transfer the chicken to a plate.
In the same pan, add the red bell pepper and carrots. Sauté for 1–2 minutes. Add the garlic and cook for another minute.
Return the chicken to the pan along with the cooked noodles and sauce. Toss everything together and cook for 1–2 more minutes. (Ensure the chicken reaches 165°F (74°C).)
Portion the Pad Thai onto plates. Top with cilantro, chopped peanuts, and lime wedges.
Serve with cucumber salad and a glass of cold apple juice.