Timefield in touch ui

Do you just need timefield and not the complete datetime xtype ?

Otherwise,

Use the dialog converter tool to convert your dialog field.

download and install DCT from the link below.

Dialog Conversion Tool

This should be the resourceType in touch UI

granite/ui/components/coral/foundation/form/datepicker

You will have to write a custom timepicker for that. There is no out of the box timepicker available in touch ui

With Touch UI - you can write a custom resource type to meet you needs (if the ootb ones do not meet your needs) -- see this where we use a Color picker as an example -- Adobe Experience Manager Help | Creating a custom Experience Manager sling:resourceType for Touch UI

You can use the type property of the DatePicker Touch UI component to "time" to only use hours and minutes.

DatePicker — Granite UI 1.0 documentation

But, depending on what your goal you might run into issues - as this stores the property as a date and not a string, as the timefield does. This could cause issues if your trying to use both dialogs while moving authors over to touch ui. Then you would need to follow Scott's advice and create a custom Touch UI Granite Component.

Additional note, some discussion around use of the Touch UI date/time picker can be found here: AEM 6.1 Touch UI: Datepicker Field not prepopulated with stored value