You want to make sure the skinnies you buy have a degree of elasticity. I was a bit worried about this, too, but I found as long as I buy stretchy jeans my feet fit through OK. They do sell jeans with zippers or velcro fasteners at the bottom, though. Regular women have the same problem. You just have to shop carefully.
BTW, I actually heard the president of Levi-Strauss recommend that buyers not wash their jeans. It sounds awful, but laundering in a washing machine and dryer destroys denim. Based on Levi's recommendations, I now turn mine inside out and air them to revive the jeans for a few more wearings. The rather than washing in a machine, I just soak them in cool bath water for awhile and hand-dry them. Unless you get excessive soiling that should do it. In fact, these days dirty looking torn up jeans seem to be more fashionable. Whatever!