Cook the pasta in a large pot of salted water until al dente (about 8-10 minutes). Then drain and set aside.
While the pasta is cooking, drain the tuna in a colander.
Peel and finely chop the onion. Sauté in a pot with a little oil, then add the tuna.
Stir in the tomato paste and whipped cream and season with salt and pepper. Let the sauce reduce slightly until creamy.
Stir the dill and pasta into the sauce and reheat, but do not boil.
Serve the dish in deep bowls. Optionally, sprinkle with freshly chopped parsley or grated Parmesan cheese. Enjoy!