I don’t know the joy of peanut butter on matzah, pop corn on passover or rice alongside the matzah balls in my soup. And that’s just a few of the foods that will not be on my table for eight days starting Wednesday. But Sephardic Jews (those of Iberian, Arabian, or central Asian descent), including the most strictly observant, enjoy them all freely. It’s one of the secret, or not so secret jealosies harbared by Ashkenazic Jews (those from central and eastern Europe).
The reason for the distinction is the way in which the legumes and legume-like products from which Ashkenazim abstain, can be milled into flour. Because part of the passover experience is not only about what we do and don’t eat, but about the conciousness we bring to it, Eropean rabbis said no to such products. In this case, if it walks like a duck and talks like a duck, even though it’s not a duck, we still treat it like one.
The other possible reason for this practice is that,

in Europe at least, beans, peas, rice and corn were often stored along with grain. Because on passover, even the tiniest amount of leavened grain is prohibited, the rabbis declared all legumes a no-no.
Whatever the reason, it makes articles like this one about the best places to eat Hummus (which my Sephardic brothers and sisters can also enjoy on passover) in New York, especially tempting. Well, not so tempting that I will change my practice, but worthy of mention. While not all the places are kosher, I can personally vouch for the ones that are, and rely on friends as committed to hummus as I am, to reccomend the others.
Enjoy!