Marinate the chicken with all of the marinade ingredients for up to 24 hours, or use it right away.
Add all of the gochujang cucumber ingredients to a bowl and mix well. Store in the fridge until ready to serve.
Place the chicken onto a baking tray lined with parchment paper and bake at 220°C (430°F) for 20 minutes, or until cooked through and the internal temperature reaches 74°C (165°F). For a slight char, switch to grill/broil for the final 5 minutes, watching closely. To air fry, cook at 200°C (390°F) for 16–18 minutes, until cooked through and lightly charred. Rest for 5 minutes, then slice into strips or dice.
Add the rice and cold water to a saucepan over high heat. Season with salt and white pepper and bring to a boil. Cover, reduce the heat to low, and cook for 12 minutes. Remove from the heat and leave covered for 4 minutes to steam. Fluff with a fork.
Serve in 5 x 750ml meal prep containers, with rice on one side, chicken in the middle, and cucumber salad on the other. Garnish with spring onion and sesame seeds, if using.