most rich actually dont have too much money but what they have the most is debts and the real rich are often poor because they are free from debts . you demand a law that is crazy , what if they hold that money for emergency use in the future . even if you hate it , its still inapropriate to force someone to donate but they can just donate if they are willing and poors shouldnt sit and depend to others but they must work hard to get out of that poverty .
yes it is right that poor people should not depend on others to get their basic necessity, their first priority should to earn money by themselves and do hard work. But there comes some condition, if the poor is unable to earn money because of some handicap or other reasons then it is the duty of rich people to help them financially.
And I think it is not a bad idea like giving specific % in money to the poor people (it is ok if the % is very very less), as we all know that ratio of poor people is much bigger that the rich one.