Tall Cans 

"Tall can" refers to a 16oz can of beer. Usually PBR (Pabst Blue Ribbon)

Has absolutely nothing to do with the middle finger.

I just had a six-pack of tall cans.

Tall Cans by L Dawg June 16, 2006

Tall Cans 

To give someone the finger. To show someone your "Tall Can" is to stick your middle finger up at them, implying "Fuck Off"

Probably best known from Transplants - Tall Cans In The Air

"Duuuuuuuude, some guy just tried to rob Joey, he punched them in the face and gave em tall cans."
"Fo Sheezy?"

Tall Cans by Shroomster November 13, 2005