Core each zucchini from the stem end. Save the pulp (the book suggests scrambling it with eggs) or toss it. Regular-size zucchini are too large; use baby ones.
Heat the ½ cup oil in a deep skillet. Fry the zucchini about 5 minutes per side until browned, in batches if needed. Drain and let cool.
In a second pan, heat the 2 tablespoons oil and cook the onion, stirring, until soft. Add the lamb, pine nuts, salt and pepper; stir until the lamb is browned, then take it off the heat.
Fill each zucchini about three-quarters full with the lamb mixture.
Put the tomato-paste water in a pan, season with salt and pepper, and bring to a boil. Lower the heat, add the stuffed zucchini, and simmer gently for 25 minutes.
Serve with plain white rice (roz abiad).