When a caucasian or white person wishes he was, dresses, speaks, and acts like a ghetto Mexican, or "Beaner", hence the term "Weaner". Replacing the "B" in "Beaner" with a "W" for "White".
"There's a couple arguing outside" says Jesse
"What do they look like?" says Leilani "Weaners." states Jesse
A phenomonon found in the mostly spanish town of Greenport on Long Island. White kids that act, talk like, and mostly chill with spanish people.
Weaner: Ay chuch, do me un favor por favor and buy me a eighteen pack of coronas, 'cuz me and my cuzins are planning to get fucked up tonite in a way you feel me essay?
Crackhead: .............what?