There are many Chinese recipes that use tangerine peel. And then there's marmalade. It also shows up a lot in Mediteranean baked foods, and you'll note that the part of the world that grows tangerines has the lowest incidence of cancer anywhere in the world.

Where to buy it.

Salvestrols are found in many fruits, they are a defence mechanism against mould. The problem is since WWII we've been spraying fruits with anti-fungals. So, when there's no mould the plant never mounts a response, so, no salvestrols. This is why you really only want to eat organic fruit, so that you get all the nutrients you pay for. Additionally, salvestrols are bitter, and by breeding the bitterness out of fruit we've been shooting ourselves in the foot, choosing sugar (bad) over salvestrols (good) - this is why growing heirloom fruits is a better choice than modern varieties.

Another vendor of Salvestrols, also in the UK, with a very good write up about the stuff. Definitely worth reading whether you order from there or are just curious.