First of all, we will make the sauce. Cook the wild fennel in a large pot of boiling salted water until tender, for 10 mins or so. Drain well in a colander and let cool, then chop and set aside.
Combine the olive oil, onion and garlic in a large saucepan and cook on medium-high heat until the onion is softened, for some 5 mins.
Add the tomato sauce, pine nuts, currants, and blanched wild fennel.
Stir the tomato paste into the wine until dissolved, then add to the sauce. Season with salt and pepper and let simmer for 10 mins.
In the meantime, make the breadcrumb topping: combine breadcrumbs and olive oil with sugad and hot pepper ina little skillet and cook, stirring constantly, until the breadcrumbs are golden brown, then set aside.
Cook the pasta al dente in a large pot of salted boiling water, then drain in a colander and stir into the sauce pan.
Transfer the pasta to a serving platter and garnish with the seasoned breadcrumbs.
If you want to make proper pasta con le sarde instead of pasta con le sarde a mare, that is to say including sardines, add a pound of fresh sardines to the sauce.