Personal Tokens: Authenticated User's ID?

I am using Personal Tokens. How can I get the user id of the currently authenticated user?

When querying, say for Tasks, I'd like to be able to filter for all tasks that are "owned" by the currently authenticated user. Essentially the "My Tasks" list in Daylite itself. In order to do this, I need the ID of the current authenticated user. I seem to locate an API call where I can find this information. Does such an API call exist?