Symptoms

The customer wants to be able to double-tap a row on an editable list view on an iPad or mobile device in order to edit a row (as you would be able to double-click on a desktop browser)
 

Diagnoses

It seems this is an iOS limitation and all browsers on a mobile device cannot double-tap or press-and-hold to edit a row in an editable list view.
 

Resolution

It seems like it is impossible to "Edit" a row on an editable list view by either double-clicking on it or pressing and holding on it. This is a limitation of the Safari Browser and the device itself, since other browsers (like Chrome) are also not able to do this.

Since the K2 Mobile app uses the Safari browser engine to display pages on the iOS device, it suffers from the same limitation.

Therefore I would suggest you build an "Edit" button into the Form/View for you to be able to edit the row on a mobile device.