1 - you have radial_slider as main container and you can get it by id: http://screencast.com/t/S26dxt3hKE
2 - inside container there is item for each minute value from 0 to 55 - total 12 values.
so easiest way to select e.g. 10min
driver.findElement(MobileBy.id("com.lge.sui.widget:id/radial_picker")).
findElements(MobileBy.className("com.lge.sui.widget.control.SUIRadialTimePickerView$RadialPickerTouchHelper")).get(2).click();
NB! my example valid as you see for LG phones only due to LG time widget customatization.