Rinse the sun-dried tomatoes. Put them in a saucepan, cover with water and cook on a medium flame for about 8 minutes. Drain keep aside a tablespoon of their water.

In a food processor, blend the sun-dried tomatoes with capers and walnuts, their cooking water and olive oil into a paste.

Collect the sun dried tomato pesto in a bowl and add the tuna, breaking it with a fork.

Cook the pasta al dente and drain it, then toss it into the bowl with the sun-dried tomato and tuna pesto.