Cut the chicken breasts and bell peppers into 1 cm cubes, cut the spring onions into fine rings, and finely chop the ginger.
Heat the sesame oil (or olive oil) in a large pan over medium-high heat. Season the chicken with salt and pepper, then add to the pan. Fry for 3-5 minutes until cooked through (74°C/165°F internal temperature). Remove the chicken from the pan.
In the same pan, fry the white parts of the spring onion, ginger, and bell pepper for 2-3 minutes.
Return the chicken to the pan, add the green parts of the spring onion, and fry for 1 minute. Deglaze the pan with soy sauce to taste.