Cumulative total per date and hour

Standard cumulative total methods should work with date/time in addition to just date. Date and date/time values are really just decimal numbers where the integer portion is the number of days since December 30th, 1899 and the decimal component is the time component. So if you FILTER your table by date/times less than your MAX date/time (in context of a visual) then it should return everything that is earlier including the time components. So if you have a date/time of 8/23/2018 1:00:00 PM then everything prior to that date and time like 8/23/2018 12:59:59 PM should be prior to that date/time and something like 8/23/2018 1:01:00 is after that date/time.

I'm not sure what you are talking about with regard to putting a column like that into a table visualization and not seeing the time component. Just use the drop down arrow on the column in the Values area and switch from Date Hierarchy to the name of your column. Then your time component will be displayed.