The only way I could see of achieving that would be to heat each face very rapidly with something like a high-powered infrared laser, so it can reach oxide-form

The only way I could see of achieving that would be to heat each face very rapidly with something like a high-powered infrared laser, so it can reach oxide-forming temperature before the heat has time to spread. The low thermal conductivity of stainless steel compared to many other metals would actually be rather useful here.