TOKYO (Reuters) - Asian shares rose on Tuesday as investor sentiment improved thanks to an overnight rally in U.S. stocks that was fuelled by better than expected earnings from Citigroup Inc , the third-largest U.S. bank, and above forecast retail sales data. Investors held onto hopes that Spain will ask for a bailout in coming weeks to activate the European Central Bank's bond buying scheme, and Greece would eventually bridge the gap on its austerity measures with its lenders, to ease fears that Athens will leave the euro zone. ...