Vietnamese "Cang Cua" or "Crab Claw" and Pepper Leaves

I'm searching for a vietnamese herb called crab claw, known in vietnamese as cang cua, meaning crab claw. Can you get this?

Among Vietnamese herbs, this is one of the least known in the West. There is a picture of it at www.nre.vic.gov.au/trade/asiaveg/thes-07.htm. Here is a closer view of the plant: www.peperomia.net/photos/b_pellucida_4.jpg.
We don't have the herb now but we are making inquiries for seeds. We should have an answer within a few weeks. We will contact you if we have any success.
Generally, in cases like this where there is a herb new to us and we can source seeds or plants, we will attempt to grow it and add it to our catalogue. We rely heavily on customer inquiries and suggestions for ideas of what new items to add to our catalogue; so thanks for your question!

Also, am wondering if leaves of green and hot peppers are edible.

Yes, they are edible. In fact, there was a move to promote the use of edible leaves of commercial crops that are normally grown for fruits or roots, and both sweet and hot peppers were on a list that I saw posted on the Internet in the mid 1990s. I don't know the current status of that effort.
Here is what the Plants for a Future database says about the leaves (https://www.ibiblio.org/pfaf/cgi-bin/arr_html?Capsicum+annuum&CAN=LATIND):
"Young leaves are said to be edible but some caution is advised. They are steamed as a potherb or added to soups and stews. The leaves contain about 4-6% protein."
I don't know what the specific concern is about the young leaves, but you can check the reference given in the PFAF database at the link cited above.
Comment from: Robert Whitehurst

[Rau Cang Cua] is actually native to the Americas, and I have it growing wild in my yard in shaded places. The old Cajuns here in Louisiana used it in their cooking. My Vietnamese wife introduced me to it some years ago. My wife says that at home in the Mekong Delta when the seeds are black and ready to fall off of the center stem, they are gathered and tossed up on the tile roof, usually mossy, and then grow there very well.