I don’t eat sandwiches very often anymore. Or more specifically bread or anything made with highly refined carbohydrate wheat flour - plus a lot sugar or very much of any ingredient that ends in -ose. But still once in a while a sandwich is too yummy looking to pass up, and not enjoy now & again.
わんぱく サンドの作り方 (レシピ) Wanpaku sando no tsukurikata (reshipi)
Which google interestingly translates as - How to make dude sandwiches (recipe).
If you are from an older generation, as I am, the Dude sandwich that comes to mind is the Dagwood sandwich.
https://en.wikipedia.org/wiki/Dagwood_sandwich
https://www.usfoods.com/great-food/recipes/black-forest-ham-dagwood-sandwich.html
But for the younger generation a “dude sandwich” may first recall the Scooby doo Shaggy Super sandwich.
This Japanese version has less bread and is a bit thinner. 
How to Make Wanpaku Sandwich (Recipe) わんぱくサンドの作り方 (レシピ)
The full details are here:
Just One Cookbook - Watch How to Make Wanpaku Sandwich
Do an internet search for - わんぱく サンド レシピ - to find other versions.
As chef John says, “Enjoy” 
