Whisk the gochujang, soy sauce, honey, rice vinegar, sesame oil, garlic, and ginger together in a small bowl.
Pat the chicken dry and cut it into approximately 1-inch pieces.
Sprinkle the chicken with cornstarch and toss until lightly coated.
Heat the neutral oil in a large skillet over medium-high heat.
Add the chicken in a single layer and cook for about 3 minutes without disturbing it.
Turn the pieces and continue cooking until browned and cooked through to 165°F (74°C).
Reduce the heat to medium and pour the prepared gochujang sauce over the chicken.
Toss and cook for 2–3 minutes, until the sauce has reduced slightly and coats the chicken.
Steam or roast the broccoli until tender-crisp.
Divide the cooked rice evenly between four meal-prep containers.
Divide the Korean chicken, broccoli, carrots, and cucumber between the containers.
Garnish with sliced green onions and sesame seeds.
Cool before sealing the meal-prep containers and refrigerate for up to 4 days.
Remove the cucumber before reheating if possible, then add it back before serving.