Cook the tortellini according to package directions.
Meanwhile, halve the leeks lengthwise and rinse under water to remove any dirt or grit. Cut the light green and white parts of the leeks into thin slices. Drain the tuna.
In a large skillet, heat the oil on medium-high. Add leeks and mushrooms and cook 7–8 min., until soft, stirring occasionally. Stir in the garlic and cook 1 min. Add tuna and tomato sauce. Reduce heat to medium and cook 5 min., stirring often. Stir in sour cream and remove from heat.
To serve, divide tortellini between 4 bowls and spoon tuna mixture on top.
Halve leeks lengthwise. Rinse thoroughly to remove any dirt or grit. Thinly slice leeks.
In large skillet, cook leeks and mushrooms in oil 7 min.
Stir in garlic and cook 1 min.
Stir in tuna and tomato sauce.
15 min. before serving:
Heat pot of water to boiling and cook tortellini according to package directions.
In medium pot, reheat tuna mixture on medium. Cook 5 min., until hot. Add sour cream and remove from heat.
Divide tortellini between serving bowls. Top with tuna mixture.