How to Make It
In a small skillet, toast the pine nuts over moderate heat until lightly browned, about 2 minutes. Transfer to a medium bowl. Add the tuna, wine and lemon zest, 1/2 cup of the cherry tomatoes and 2 tablespoons each of the olive oil and fennel fronds. Cover and refrigerate for 1 hour.
Heat the remaining 2 tablespoons of olive oil in a large, deep skillet. Add the crushed red pepper and the remaining cherry tomatoes and cook over low heat, stirring occasionally, until the sauce is flavorful, about 10 minutes.
Meanwhile, cook the linguine in boiling salted water until al dente. Reserve 1/4 cup of the pasta cooking water, then drain the linguine.
Add the tuna mixture and the remaining 2 tablespoons of fennel fronds to the skillet and cook over low heat, stirring just until the tuna starts to whiten, about 1 1/2 minutes. Remove the skillet from the heat. Add the linguine and the reserved pasta cooking water and toss well. Season with salt and pepper and serve at once.