Which buddhist traditions use silent visual applause, instead of clapping, to show appreciation and what is the origin of this practice?

Well there is a link to a book of etiquette that says "Hindu hosts are ..... waving fingers." www.read-write-now.org/UserDir/Documents/Cultural%20Etiquette.pdf

A Chinese tradition for shaking hands involves waving hands up and down https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ved=0CEkQFjAG&url=http%3A%2F%2Fpeople.wku.edu%2Fhaiwang.yuan%2FChina%2Fdocs%2Fchinesecultureandcustoms.rtf&ei=9RxkVIb1JOmJsQTUzYD4DQ&usg=AFQjCNGd2Lid0ya_JeNnvRfMeNPpg7Xu8w&bvm=bv.79189006,d.cWc

The traditional Chinese ‘handshake’ consists of interlocking the fingers of the hands and waving them up and down several times. This is today rarely used (except during festivals, weddings and birthdays of the elderly), and the western style handshake is ubiquitous among all but the very old or traditional.

Of course whenever you talk about clapping and Buddhism you get the sound of one hand clapping, a traditional koan.

I replied to hopefully get some discussion going on this interesting topic. Unfortunately my googling has not show me much more. Thank you for the question.

This video says that it's widespread among French and German university students, ecologists, especially left-wing, for example at political assemblies and unions. And it says that an internet search shows that it's part of the "language of signs" but that no-one knows which country it began in.

The page Monks and nuns from the Thich Nhat Hanh collective, in Plum Village, France, pay our school a special visit suggest that Thich Nhat Hahn are:

• From France
• Teaching 'silent applause'
• Teaching 'ecologist' songs such as "I love nature"

So perhaps they adopted the gesture from that milieu (or vice versa): i.e. from European students and young ecologists.

The Sound of One Hand = "quiet sound" (Soundless Sound - Emptiness)

At some point, completely quiet heart that does not even sound that can make us being distracted. Ears are hearing is still heard, but absolutely not disturbed mind. It is "beyond" all sound.

That is, in silence we "hear", "see", "understands" or "enlightenment" is many things, but when the mind is being distracted because of the "noise" we do not hear, do not see, do not understand.

The Sound of One Hand (101 storie Zen -Nyogen Senzaki)

The master of Kennin temple was Mokurai, Silent Thunder. He had a little protégé named Toyo who was only twelve years old. Toyo saw the older disciples visit the master’s room each morning and evening to receive instruction in sanzen or personal guidence in which they were given koans to stop mind-wandering. Toyo wished to do sanzen also.

“Wait a while,” said Mokurai. “You are too young.”

But the child insisted, so the teacher finally consented.

In the evening little Toyo went at the proper time to the threshold of Mokurai’s sanzen room. He struck the gong to announce his presence, bowed respectfully three times outside the door, and went to sit before the master in respectful silence.

“You can hear the sound of two hands when they clap together,” said Mokurai. “Now show me the sound of one hand.”

Toyo bowed and went to his room to consider this problem. From his window he could hear the music of the geishas. “Ah, I have it!” he proclaimed.

The next evening, when his teacher asked him to illustrate the sound of one hand, Toyo began to play the music of the geishas.

“No, no,” said Mokurai. “That will never do. That is not the sound of one hand. You’ve not got it at all.”

Thinking that such music might interrupt, Toyo moved his abode to a quiet place. He meditated again. “What can the sound of one hand be?” He happened to hear some water dripping. “I have it,” imagined Toyo.

When he next appeared before his teacher, he imitated dripping water. “What is that?” asked Mokurai. “That is the sound of dripping water, but not the sound of one hand. Try again.”

In vain Toyo meditated to hear the sound of one hand. He heard the sighing of the wind. But the sound was rejected.

He heard the cry of an owl. This was also refused.

The sound of one hand was not the locusts.

For more than ten times Toyo visited Mokurai with different sounds. All were wrong. For almost a year he pondered what the sound of one hand might be.

At last Toyo entered true meditation and transcended all sounds. “I could collect no more,” he explained later, “so I reached the soundless sound.” Toyo had realized the sound of one hand.