How can I relax or meditate in a public workplace?

Very simple. In a public workplace, you don't need any particular posture or equipment to meditate. Any activity you do can serve as a meditation -- from washing the dishes, to working on a computer, to answering the phone. You are practicing being present to exactly what you're doing. Jon kabat-zinn's book, "wherever you go, there you are, " gives many everyday life examples & lessons.