3 ways I can think of.
Nothing pretty or natural though. The problems are that there is no standard control in SSRS, and there is no control data to use to manage layout in a standard control
First, Generate a dummy column, say using ROW_NUMBER() and modulo 2.
Use this to filter the dataset results into 2: bind each filtered set to side by side tables.
Second, use a matrix control in a rectangle
This will split pairs of rows about to side by side, use the rectangle grouping to split into pairs. You'll need a dummy column again to group on but going up 0, 0, 1, 1, 2, 2 (hmmmm how to do that...)
Third, generate the dataset as 2 columns.
Self-join or PIVOT using a ROW_NUMBER() and modulo 2 column
Personally I'd tend to the 3rd option or 1st option.