Taopaipai and Bukujutsu

[Bussani]

Herms' guide simply says that it's a technique of the Tsuru-sen school, so I assume Tenshinhan learned it from Tsurusennin.

Kikoho [Ki Manipulation Cannon]
First Appearance: Chapter 133
Category: ki manipulation
People: Tenshinhan
Special Characteristics: The secret weapon of the Tsuru-sen School. It concentrates a kiai into one point, then releases it in a single burst. Its main difference between ki blast-type techniques is that its trajectory cannot be seen. Its destructive power is formidable enough to instantly obliterate the Tenkaichi Budoukai arena. Indeed, it is characteristic of the techniques from the Tsuru-sen School, whose objective is to mercilessly kill people. Because this technique heavily uses up one’s internal energy, it can only be used to decide the match in a single shot. (Daizenshuu 2, p.206/Daizenshuu 4, p.111)



Shin~ [New~]
First Appearance: Chapter 373
People: Tenshinhan
Special Characteristics: A technique that increases the force of the Kikoho. An attack that becomes possible when one has improved their abilities through intense training. Tenshinhan fired this technique to stop Cell from moving when Cell was trying to absorb No.18, but he used up all of his power and collapsed. (Daizenshuu 4, p.112)

[Herms]

Is it ever explicitly stated in the manga how and when he trained for #22?

It's at the end of chapter 113. After Goku meets up with Jacky Chun and says he won't lose this time, Jacky thinks to himself about how he's been training in secret. Then in the next chapter, after Jacky beats a bear guy, Yamcha comments on how his technique has improved.