Dashimaki: This is a regular item in Izakaya and sushi bar*. "Otsumami yokocho" also have the recipe (volume 1, p64) but this is a rather standard affair and I made it in the way I usually make it. Although you could make this in a regular round frying pan, to make the omelet in a proper rectangular shape, you need to use a rectangular frying pan. I have a small home-cook version with a nonstick surface as seen below.
*Especially in Kyoto, dashimaki appears to be extremely popular. We found stores in Nishiki market 錦市場 specialized in all kinds of dashimaki variations. In the morning, in one such store, we saw 5-6 cooks lined up shaking large square pans up and down making dashimaki to be sold for the day. Many Kyotoites appear to just come and buy these large rectangular omelets.
I used brown eggs (3 large), dashi broth (3 tbs or 1 tbs per egg), sugar (3 tsp or more if you like it sweet) and salt (a small pinch). I mixed all ingredients using cooking chopsticks. In a square frying pan on medium-low flame, I add vegetable oil (1/2 tsp) and add the egg mixture (just enough to cover the bottom in a thin layer. As the bottom sets but the surface is still wet or uncooked, I start rolling from one end using chopsticks and/or silicon spatula (If you are a dashimaki Jedi, you use only chopsticks). You repeat this several times and keep rolling. It is important to lift the already cooked omelet so that the new egg mixture will flow under it. For my pan, three eggs makes a perfect rectangle omelet which is even with the height of the pan's edge (left lower). I press against the vertical rim to make the two long ends straight. Here is a visual aid by a pro.
Since my omelet was near-perfectly formed, I did not have to use a sushi bamboo mat to shape the omelet. On the right above, you can see the cut surface with multiple layers.
Sushi Rice: As usual, I used sushi vinegar from the bottle. I added as much as the rice would absorb. I let it sit for few minutes after the rice was lightly mixed while the rice was fanned (by my wife).
I sliced the omelet into one inch thick slices and then cut each slices in diagonal. I placed them on the vinegared rice as seen in the first image. After placing slices of smoked salmon, and sliced avocado, I added a small mound of real wasabi and sprinkled soy sauce on the avocado. I garnished it with nori strips. Marinated tuna would have been better but this is a mighty good "shime" 締め.
...and also as a starter dish for the next evening.