I don't want to derail this into a rule discussion but really, how would you do that in 3e/4e beyond DM fiat? And won't "experienced" DMs handle those ad hoc rules better than the novice DM who might not even allow it. After all, there are no "pick up random large objects and fling them" rules in either game. It sounds like a ranged trip attempt (as you hope to knock them down, right?) Maybe give them unwanted cover (there's a table on your chest and you are prone).
Thats a really good question.
There's a plethora of "actions" a PC could take in a combat that there aren't really rules for.
Some GMs may have a penchant for nerfing those actions, for fear of it becoming overpowered or overused.