Pistachio Pesto Pasta with Tuna Tartare

0 Marinate the tuna. Add the cubed tuna to a mixing bowl with the olive oil, soy sauce, sesame oil, lemon zest, ginger, and a small pinch of salt. Gently toss to combine, cover, and refrigerate while you prepare the pesto and pasta.
1 Make the pistachio pesto. Add the pistachios, basil, garlic, lemon juice, olive oil, and salt to a food processor. Blend until completely smooth, scraping down the sides as needed.
2 Cook the spaghetti. Bring a large pot of generously salted water to a boil. Cook the spaghetti until al dente according to package directions. Reserve some pasta cooking water before draining.
3 Toss with the pesto. Add the pistachio pesto to a large stainless steel mixing bowl. Add the hot spaghetti and toss vigorously, adding a splash of reserved pasta water at a time until the pesto becomes creamy and evenly coats the pasta.
4 Plate. Twirl the spaghetti onto each plate. For the nigiri-inspired presentation, shape it into a horizontal nest.
5 Finish and serve. Spoon the chilled tuna tartare over the pasta, finish with fresh chives, and serve immediately.