You can control the spaces between columns in the Row using Row and Column Settings.

Remove Spaces Between All Columns in the Row

You can remove the spaces between all columns by doing this;

Row Settings - Advanced - Set Separator to None

Control Spaces Between Columns

You can control the spaces between columns the way you want using this option:

To control the spaces on the right side of the first column for example:

Open column Settings

Then Advanced
Add the space value in the margin right
If you want to increase, add the value in +
If you want to reduce, add the value in -