Hey, Einar,
On #1, let's say that when you designed the report, you utilized some type of schema definition (maybe from XML or other data source) that had two data tables...DtHeader and DtDetails.
At report runtime, you can do...
oMyReport.Database.Tables[0].SetDataSource(DtHeader);
oMyReport.Database.Tables[1].SetDataSource(DtDetails);
On #2...while I've never actually tried it...if you report is nothing but labels and no data, I would "guess" you'd be able to generate the one-page report without a 1-row table. But you'd have to give it a try to be sure.
Also, the link Eric gave you is a good one...Eric Bischoff's book is definitely the best book for CR.net
Kevin