In the portal engine there a couple web parts to show reports. I think at the end they all based on
\CMSModules\Reporting\Controls\DisplayReport control. You can dig inside to see if can get something out and plug this in MVC. I think they still heavily using asp.net controls.
There are different report types (table, graph, value) if lets say you want to use table report - it would be easier to get the query from Reporting_ReportTable and run it yourself. There is reporting api but it is for managing reports. but it should not be complicated to render a table. You can start with that.