Cris Carter Gives Hand Advice to Odell Beckham, Size Matters!

Cris Carter had a private 1-on-1 training session with Odell Beckham Jr. -- and told the NY Giants superstar the 5-fingered secret to dominating in the NFL.

The two WRs hooked up at Brick gym in L.A. -- where Carter dished out a few route-running tips before focusing on OBJ's mitts.

It's hard to make out exactly what Cris said but the message seemed pretty clear -- work on stretching out the wingspan on your hands!!

At one point, Carter tells Odell that he should hire someone to work on his hands the way they work on his body -- "These are your moneymakers right here!"

Beckham has been MIA from Giants' OTAs all week -- but we're guessing the team will be happy to see he's still working out ... right?