"second" ASL American Sign Language

SECOND: As in "a second of time."
The sign for "MINUTE" is often used to mean "second." See: MINUTE
Yes, I know that is lame. Having two concepts that use the same exact sign and rely on context or a mouth movement to distinguish between the two meanings. I didn't invent the language, I'm just teaching it to you.
Do a very quick twitch of the right hand in an "index finger" handshape. Have it do one "tick" of the clock. The movement is from the wrist and pivots on the heel of the other hand. Remember, the movement is small and quick.

If you are discusing duration of time and you need to clearly distinguish between a "minute" and a "second" -- you can spell them out. M-I-N and S-E-C.
Or sign "MINUTE" and spell S-E-C.

OPTIONAL READING:
"Second hand"
In a message dated 10/29/2006 1:23:31 PM Pacific Standard Time, rollendonner@ writes:

I learned a "new" sign today that [my] teacher hadn't known before: apparently the local slang for "used car" is signed with an "L" sign with the index finger pointed away from you like a pistol (at about a 45 degree angle) and shaking it back and forth a few times--like prodding someone with a gun to buy a car they don't really want? The person who had learned it from Deaf friends had no explanation but swore that it was true.

Loren,
Actually, the sign you are describing is based on a sign that means "second" as in "I second that motion," or "used / second-hand."
When at a board meeting if we want to second something we will use the "L" hand pointed somewhat forward and up. The movement is a forward/sideward roll with a quick ending.
If you roll the sign toward a person that sign can also be used to mean, "it's your turn."
When this sign is used for cars it means "a second-hand car."
Bill