Hunter's Funeral Pyre

Pyre A structure, usually a mound of wood, that is used for burning a body as part of a funeral rite. The body is placed upon the pyre and the pyre is then set on fire. In a Viking Funeral the pyre was built on a ship, which was then sent out to sea as it burned. – Pad of Definitions (2.02 Everybody Loves a Clown), Official Website

A funeral pyre is a traditional form of cremation in some cultures, particularly in the Hindu religion (Source). The pyre is usually a raised wooden platform on which the corpse, either in a coffin or wrapped in a shroud, is placed for cremation.

In Supernatural, the funeral pyre appears to be a tradition for fallen hunters. Salting and burning the corpse also has the practical outcome of ensuring the person does not return as a vengeful spirit or similar entity. The images here of a warrior's death also recall the famous scene of the funeral pyre of Darth Vader in Return of the Jedi.

Interestingly, on none of the many occasions when Sam and Dean die have they been cremated. When Sam is killed by Jake, Bobby suggests they burn his body, but Dean resists. Dean, after digging his way out of his grave after being raised from Hell, expresses surprise that he was buried, not cremated:

Bobby: These last months haven't been exactly easy, you know. For him or me. We had to bury you.
Dean: Why did you bury me, anyway?

Bobby: I wanted you salted and burned. Usual drill. But... Sam wouldn't have it.

Jo and Ellen are given a symbolic pyre, when their photo is burned in Bobby's fireplace.

Rufus Turner would have been accorded a pyre, but the Jewish tradition forbids cremation. So Rufus is buried, in what is obviously a Jewish cemetery, rather than given a hunter's funeral pyre. Bobby pours some of Rufus' favorite drink - Johnny Walker Blue Label - on the grave.

Bobby is salted and burned by Sam and Dean, although it is not shown. Later, as a ghost, Bobby understands that he is becoming a vengeful spirit, and asks Sam and Dean to burn his flask, his last link with the living world, in a second pyre.

Annie Hawkins requests a hunter's funeral after she is killed by Whitman Van Ness, which Sam and Dean carry out.

Appears in 2.02 Everybody Loves a Clown Following John's death, after making a deal for Dean's life with Azazel, Dean and Sam burn him on a pyre.	Appears in 3.01 The Magnificent Seven Following the battle with the Seven Deadly Sins, Sam burns the bodies of the demons that Ruby killed. The camera cuts to Tamara burning Isaac on a pyre.	Appears in 4.19 Jump the Shark Sam and Dean give their half-brother Adam Milligan a hunter's funeral following his death at the hands of ghouls.
Appears in 5.10 Abandon All Hope... There are no bodies to burn following Jo and Ellen's sacrifice to stop the hellhound, so Sam, Dean and Bobby give them a hunter's farewell by burning the photo of them.	Appears in 5.15 Dead Men Don't Wear Plaid When his wife Karen Singer comes back as a zombie, Bobby has to kill her - for the second time.