If using fresh sardines, butterfly them: remove head and most intestines, remove center back fin with attached bones, open flat along the spine, loosen and pull out the spine with the tail, then rinse and drain. If using canned sardines, start with the next step.
Wash finocchio tops or wild fennel. Boil 4 to 5 quarts water, salt it, add the greens, and cook 10 minutes with the cover set on askew. Lift out greens with a colander spoon and keep the water for the pasta later.
When greens are cool enough to handle, squeeze gently to remove moisture and chop.
Soak raisins in several changes of cold water at least 15 minutes. Drain and chop.
Bring water to a lively simmer in a saucepan.
In a saute pan that will hold all sauce ingredients, cook onion in olive oil over medium heat until translucent. Set the pan over the simmering water, add anchovies, and mash and stir constantly until nearly dissolved into a paste.
Put the pan back over medium heat, add the chopped greens, and cook 5 minutes, stirring from time to time.
If using fresh sardines, push sauce to one side, cook sardines in batches without overlapping, less than 1 minute per side, then move them aside and continue until done. If using canned sardines, skip to Step 9.
Add pignoli, raisins, tomato paste-saffron solution, salt, and black pepper. Cook over medium heat until the liquid bubbles away. If using canned sardines, add them now, turn them in the sauce 2 or 3 times, then remove from heat.
Bring the fennel cooking water back to a boil, salt it lightly, and cook the pasta in it.
Toss pasta with the sardine sauce. Add bread crumbs, toss again, let it settle a few minutes, and serve.