Heat the oil in an ovenproof frying pan and fry the chicken for 2-3 minutes on each side, or until golden-brown. Add the chickpeas and cook for a further 1-2 minutes. Transfer to the oven and roast for 5-7 minutes, or until the chicken is cooked through. (The chicken is cooked through when the juices run clear when pierced in the thickest part with a skewer.) Remove the chicken breast and chickpeas from the oven and shred the chicken breast.
Mix the remaining salad ingredients in a bowl with shredded chicken and chickpeas.
For the herb oil, blend all the ingredients in a food processor until smooth.
To serve, place the spinach leaves on a serving plate, top with the salad and spoon the herb oil on top.