I want to make sure my users know the list, I am presenting them for the first time, is slidable. So I was thinking about randomly sliding one item so my users are aware of that option. How would I trigger that with js or css?

It seems that these buttons are simply hidden beneath the element they apply to. I noticed on my app, when the hidden button is visible, there is a CSS transform applied to the element.
In my case, the transform applied is -70px. Here is the relevant style:
style="transform: translate3d(-70px, 0px, 0px);"
You would want to experiment to find the appropriate value. I would suggest that you create a special CSS class that you can apply to the element that would force it to apply the transform. Tie the class to a component property. Then, in your code, set that property to true for a brief period of time, and then back to false.
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