1 Rinse scallions and cut into thin slices. Rinse cucumbers thoroughly, wipe dry and cut into thin strips.
2 Rinse tuna fillet briefly. Pat dry and cut into 1 cm (approximately 1/2-inch) thick slices. Season with salt and pepper.
3 Coat a grill pan with oil. Sear tuna for just under 1 minute on each side. Use a large knife to cut tuna into thin strips.
4 Break soba noodles into pieces and cook according to package directions in boiling, salted water until al dente. Drain in a sieve, rinse under cold water and drain well.
5 Finely chop pickled ginger. In a bowl, mix ginger, soba noodles, scallions, soy sauce, vinegar and wasabi paste.
6 Place 1 sheet of nori shiny side down on a bamboo sushi mat. Place 1 serving of noodle mixture on the lower 1/3 of the sheet. Add cucumber and tuna strips.
7 Starting with the edge closest to the filling, roll the sushi using the bamboo mat, applying a little pressure while rolling.
8 Brush the upper edge of the nori sheet with a little water before rolling the edge to seal. Repeat with the remaining nori sheets and the remaining noodle mixture to make 5 more maki rolls. Dip a sharp knife in water before cutting each roll into 4 pieces. Serve.