The speech in Persian is here:
Sorry that I misremembered the exact phrase Ahmadinejad had used. He made an analogy to Khomeini's determination and success in getting rid of the Shah's government, which Khomeini had said "must go" (az bain bayad berad). Then Ahmadinejad defined Zionism not as an Arabi-Israeli national struggle but as a Western plot to divide the world of Islam with Israel as the pivot of this plan.
The phrase he then used as I read it is "The Imam said that this regime occupying Jerusalem (een rezhim-e ishghalgar-e qods) must [vanish from] from the page of time (bayad az safheh-ye ruzgar mahv shavad)."
Ahmadinejad was not making a threat, he was quoting a saying of Khomeini and urging that pro-Palestinian activists in Iran not give up hope-- that the occupation of Jerusalem was no more a continued inevitability than had been the hegemony of the Shah's government.
Whatever this quotation from a decades-old speech of Khomeini may have meant, Ahmadinejad did not say that "Israel must be wiped off the map" with the implication that phrase has of Nazi-style extermination of a people. He said that the occupation regime over Jerusalem must be erased from the page of time.
Again, Ariel Sharon erased the occupation regime over Gaza from the page of time.
I should again underline that I personally despise everything Ahmadinejad stands for, not to mention the odious Khomeini, who had personal friends of mine killed so thoroughly that we have never recovered their bodies. Nor do I agree that the Israelis have no legitimate claim on any part of Jerusalem. And, I am not exactly a pacifist but have a strong preference for peaceful social activism over violence, so needless to say I condemn the sort of terror attacks against innocent civilians (including Arab Israelis) that we saw last week. I have not seen any credible evidence, however, that such attacks are the doing of Ahmadinejad, and in my view they are mainly the result of the expropriation and displacement of the long-suffering Palestinian people.
It is not realistic for Americans to call for Iran to talk directly to the Israeli government (though in the 1980s the Khomeinists did a lot of business with Israel) when the US government won't talk directly to the Iranians about most bilateral issues. In fact, an American willingness to engage in direct talks might well pave the way to an eventual settlement of these outstanding issues.