The most common and most likely answer to this crossword clue is the 5 letter word SPIEL
S
P
I
E
L
More clues leading to the result SPIEL
Buddy explains!

The straight part
We know that "Salesman's talk" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case salesman's talk = spiel.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SPIEL mean?
SPIEL noun- A lengthy and extravagant speech or argument usually intended to persuade.
- An early form of rap music.
- To talk at length.
- To give a sales pitch; to promote by speaking.
- A game of curling.