The day before, make the dressing. Mix the tomato paste and vinegar in a small bowl. Slowly whisk in the olive oil to form a smooth emulsion and season to taste. Store it in a screw-top jar if you want to get ahead and rewhisk before using on the night.
The pine nuts can be dealt with the day before to save time. Heat a small frying pan, tip in the nuts and cook for 2-3 minutes, turning them frequently until they smell nutty and are nicely browned.
To serve, put the leaves in a large bowl with the tomatoes and olives. Pour in the dressing and mix well, then divide between eight glasses and sprinkle with the toasted pine nuts.