Heat oil in a large skillet over medium heat. Add chicken and onion; sauté for 5-6 minutes until chicken is sealed.
Move chicken aside and add green curry paste, ginger, and garlic in the center. Stir-fry for 1 minute.
Pour in coconut milk and stock; add bell pepper and green beans. Simmer for 4-5 minutes until thickened.
Stir in sugar, then squeeze lime juice for flavor adjustment.
If using bean sprouts, add them now and cook for an additional minute. Finish with baby spinach.
