What is the ruling on using the Visa cards issued by the company to its employees for receiving their salaries from the bank, and is this considered participating with the bank and assisting it in its activities?

It is not permissible to deal with usurious banks, because it involves aiding them in their forbidden activities. Banks benefit from financial liquidity in their usurious operations, and the sin of aiding falls upon the company or entity that deposits funds in the bank. As for the employee, there is no sin upon him if he finds no alternative, and he is permitted to use the bank's ATM card.