Heat half the oil in a large saucepan over medium-high heat; add chicken and cook for 3 to 4 minutes or until browned. Transfer chicken to a plate.
Heat remaining oil in pan. Add onion and cook, stirring, for 3 to 4 minutes or until softened. Stir in garlic and curry powder. Add rice and stock and bring to the boil; reduce heat and simmer, covered, for 10 minutes.
Add cauliflower and browned chicken; cook, covered, for 5 minutes. Add beans and cook, covered, for 2 to 3 minutes or until chicken is cooked through, the rice is tender and the liquid has absorbed.
Stir in lemon juice and freshly chopped coriander.