By Brian O’Connell Don’t leave cash, benefits and perks on the table at work With tension tightening in the U.S. employment market, career professionals may think they’re losing leverage with an employer on key issues like pay, perks, and benefits. That’s really not the case for employees who bring talent and tenacity to the job – and to the negotiating table when hashing out a deal with new employers. “More is available for negotiation than either the prospective employee or the employer realizes,” said Venn Negotiation founder Christine McKay told TheStreet in an interview. “In my years of n…