Many small gentlemen knives made with brushed stainless steel scales/liners would do the job. Some with locking blades are made by: Ka-Bar, Buck, Camillus, Bear MGC.
I carry a Schrade green handle small lock-back (5OT) in my jeans all the time. That might be a bit large for your Altoid can but sturdy and inexpensive (~$20).
HM