Ok so the hurling rage power states that the thing you throw does falling damage. If you hurl something like a star knife does it deal weapon damage as well?
Another point is that the item thrown gets your strength mod, if you throw it two handed does it get the strength mod like a two handed sword does?
It also states that power attack can be added to the attack. Does that mean it is a melee attack? If it isn't a melee attack can you use deadly aim? If it isn't a ranged attack can you use the halflings feat risky striker with it?
Also can one get sneak attack damage with the object thrown?
If you are using one hand to throw an object can you use two weapon fighting to throw two objects?
To answer your first question: why would you want to hurl a star knife when you can throw it normally? I guess that's not a great answer, but the idea behind this rage power is that you're going to be throwing wagons and boulders etc. If I were you, I would avoid unnecessary confusion and stick to the big things. In any event, I would rule that the star knife only deals falling item damage as an appropriate item of its size, not the weapon damage.
Second question: The power describes the damage dealt very specifically:
This inflicts damage as a falling object (Core Rulebook 443) plus the barbarian's Strength bonus.
RAW, this means that regardless of how many hands you use to throw the item, you apply only your flat STR bonus. If your DM was willing to make liberal interpretations, the feat Two-Handed Thrower might get you that extra 1/2x STR mod to damage.
Third question:
This is a ranged touch attack, and the target may attempt a Reflex save (DC 10 + 1/2 the barbarian's level + the barbarian's Strength modifier) for half damage.
Fourth: Sneak attacking usually requires you to be within 30ft, but if you meet that requirement, I see no reason outlined in the rules why you couldn't sneak attack with a thrown boulder.
Fifth: Usually, you can throw multiple weapons with TWF, but because using the power is a separate full-round action which includes only the throwing of one item, you would have to use two full-round actions to throw two items.
Thank you for the clarification solitary.