Image credit to: Katie Bornn
Bring large saucepan of water to a boil. Add noodles and cook according to package directions. Drain, rinse with cold water and set aside. Or cook rice.
Whisk 6 Tbsp water, mirin, soy sauce and cornstarch in a small bowl. Set aside
Whisk red pepper paste, garlic and hot water together in a medium bowl.
Slice chicken into thin strips and place in bowl with red pepper paste. Let marinate in fridge.
Heat oil in a large skillet over medium heat. Add onion (and green stems, if using) and cook, stirring occasionally, until beginning to soften, 2 to 3 minutes. Add bok choy (leafy greens, if using) and carrots, stirring occasionally, until beginning to soften, about 5 minutes.
Add chicken and red pepper marinade; cook, stirring, until the chicken is just cooked through, about 5 minutes.
Whisk cornstarch mixture again, add to pan and bring to boil. Cook, stirring, until sauce has thickened, 2 to 4 minutes. Serve over noodles (or rice). Garnish with sesame seeds.