Season chicken with salt and brown in the oil in a large saucepan over medium heat until almost cooked through. Remove chicken from pan and set aside.
Add onion, garlic, carrots and celery to pan and cook gently until tender. Stir in ginger, paprika, cumin, oregano, cayenne pepper and turmeric. Stir fry for about 1 minute, then mix in stock and crushed tomatoes. Return chicken to pan, reduce heat to low and simmer for about 10 minutes.
Add chickpeas and zucchini to pan and bring to a simmer. Cover pan and cook for about 15 minutes, or until zucchini is tender. Stir in lemon juice and serve.