Truncate, but display the complete name on
hover using for example an overlay superimposed over the original.
My error: this question is about mobile that has no hover! (thanks @Sheff) And touching the truncated name is not an option, because the finger would obscure the expanded name most of the times.
I'd try a button below the names column (I'm assuming there is one such column) that, when touched and only while touched, would enlarge the names column width allowing the names to be seen in full.
The user might want to see the names in the list, but maybe not the full name all the time.
Also, account for cultural differences when defining the with and the font size of the user names column. Maybe in your culture the names are short and monosyllabic, like "John Doe", while other cultures like in Spain or Colombia have double first names and double family names.