Heat the oil in a saucepan, add the onion, garlic and sage and cook over a low heat, stirring frequently, for 5 minutes. Add the pumpkin and beans and stir well, then add the stock and a little salt and pepper.
Bring to the boil, then reduce the heat, cover and simmer gently for 30 minutes until the pumpkin is tender. Transfer the soup to a food processor or blender and process until smooth. Return to the pan, adjust the seasoning and heat through.
Meanwhile, make the salsa. Chop the olives and mix with the oil, lemon rind, parsley and salt and pepper in a bowl.
Serve the soup in warmed bowls, topped with spoonfuls of the salsa.