Heat the oil in a heavy skillet, add the carrot, onion, fennel, and minced ginger, and saute over medium heat until the vegetables are tender. Allow the mixture to cool briefly, then mix in the tuna and ricotta. Season with salt and pepper.
Spread 3 sheets of fresh pasta on a lightly floured work surface. Place slightly rounded tablespoonfuls of the filling 2 inches (5 cm) apart on the pasta. Brush some of the yolk-water wash around each mound of filling.
Cover with the remaining pasta and, using a ravioli cutter or a knife cut squares around the mounds of filling. Seal the edges by hand or with the tines of a fork.
Arrange them on a platter and dust them with a semolina so they do not stick.
Refrigerate until ready to serve.
Heat the canola oil in a heavy skillet. Add the ginger and fry it over medium-high heat until it is lightly browned.
In a separate pan, melt the butter over medium heat. Add the tomato and stock, cook for 5 minutes, then add the tarragon. Season with salt and pepper.
Bring a large pot of water to a boil, add the ravioli, reduce the heat, and simmer about 6 minutes.
Drain, then divide the ravioli among 6 plates.
Reheat the tomato sauce and spoon some of it over each portion.
Top with fried ginger and serve.