Wash the sushi rice in a bowl covered with cold water and drain in a sieve. Repeat the process until the water that runs off is clear. Drain the rice in the sieve and place it in a heavy-bottomed pot with approx. 230 ml of cold water. Soak rice for 30 minutes. Bring the rice to the boil over medium heat with the lid slightly open and cook for 2 minutes. Reduce the temperature to the lowest setting, place a kitchen towel between the pot and the lid, and cook the rice covered for 20 minutes. Remove the pot from the heat and let the rice sit for another 15 minutes. Mix vinegar, sugar and salt in a small saucepan and heat gently until the sugar has dissolved.
Pour the rice into a shallow wooden or plastic bowl and gradually work in the vinegar mixture with a wooden spatula. Cover the rice with a damp cloth and let it rest for 20 minutes.
Boil eggs in boiling water for 8 minutes, rinse with cold water, peel and dice approx. 1 cm in size. Rinse the chives, shake dry and cut into fine rings. Mix chives with mayonnaise and wasabi paste. Mix the diced eggs loosely with the mayonnaise and season with salt and pepper. Cover and set aside until further use.
Halve the avocado, remove the core, peel the halves and cut the flesh into fine wedges. Rinse radish and red cabbage. Peel the radish, slice the radish and red cabbage approx. 1 mm thin. Peel the papaya and dice it into cubes of about 5 mm. Rinse the coriander, shake dry and finely chop using the tender stems. Mix the avocado, radish, red cabbage, papaya, 2/3 of the coriander, sesame oil, lime juice and 2 tablespoons of sesame.
Place 1 nori sheet with the rough side up. Spread about 1½-2 tablespoons of rice in the middle. Spread the rice a little with moistened fingers so that there is a 5 cm wide edge on the sheet all around. Spread ¼ of the avocado filling over the rice. Cover the filling with 1 tablespoon of rice, carefully spread it on top and flatten it slightly. Lightly moisten the edge of the sheet and fold it over the filling and press it down to create a closed, flat package. Fill the remaining leaves in the same way and make 3 more packets. Halve each packet. Sprinkle the wasabi mayonnaise with the remaining sesame seeds (1 teaspoon). Serve sandwiches with mayonnaise and remaining cilantro.