Bring a medium pot of salted water to a boil. Cook the noodles according to the package directions until al dente. Drain thoroughly, toss with a small amount of oil to prevent sticking, and set aside.
Cut the chicken into approximately 1-inch bite-sized pieces. Place the chicken in a bowl, sprinkle with the cornstarch, and toss until each piece has a light, even coating.
Heat the vegetable oil in a large skillet or wok over medium-high heat until shimmering.
Arrange the chicken in a single layer, avoiding overcrowding the pan. Cook for approximately 4–5 minutes per side, or as needed, until golden and completely cooked. Chicken should reach a safe internal temperature of 165°F (74°C).
Transfer the cooked chicken to a clean plate.
Reduce the heat slightly. Add the minced garlic and grated ginger to the same skillet. Cook for 30–60 seconds, stirring frequently, just until fragrant. Avoid letting the garlic burn.
Add the soy sauce, honey, and optional red chili flakes. Stir continuously and let the mixture gently bubble for 2–3 minutes until it becomes slightly thicker and glossy.
For an even thicker sauce, combine 1–2 teaspoons cornstarch with an equal amount of cold water. Gradually stir the slurry into the simmering sauce until it reaches your preferred consistency.
Return the chicken to the skillet and toss for approximately 1 minute until thoroughly coated in the sauce.
Add the cooked noodles and toss until everything is hot and evenly covered in the sticky sauce. This is what gives Sticky Garlic Chicken Noodles their signature glossy finish.
Remove from the heat and sprinkle with chopped green onions and optional sesame seeds. Serve immediately.