One if Iran's stated foreign policy goals is NOT the elimination of Israel, as comment here notes. What Iranian leadership has said repeatedly is that they hope for and expect the fall of the Zionist regime. A regime can fall (as the communist USSR) while the country remains. And when Zionism does fall, perhaps the land can be called Palestine once again - and Jews, Muslims and Christians can live side-by-side, as they throughout much of history.
from the article: U.S., Iran seek closer ties alongside nuclear program