Heat oil in a skillet over high heat. Add chicken and sear until browned, about 3 minutes. Remove and set aside.
Reduce heat to medium-high. Add onion, garlic, and ginger. Stir for 1 minute.
Stir in red curry paste and cook for 1 minute more.
Add coconut milk, fish sauce, and brown sugar. Simmer gently (don’t boil).
Return chicken to pan with green beans and bell pepper. Simmer 8 minutes until tender.
Turn off heat. Stir in basil and lime juice.
Serve hot over rice. Garnish with cilantro.
