When you insert a new table using the editor, by default the table is made to be transparent.
However, in order to make a table that isn't transparent transparent, here is what you have to do:
1) Highlight the Table, then right click and choose Cell, then Cell properties.
When the Cell properties pop up window appears, you will see Background Color and Border Color in the lower right of the window.
3) "Border color" and "Background color", both need to be empty in order to make the table
transparent. If you see any text in either of these fields, then delete
it completely. Once both fields are empty, click the "OK" button at
the bottom of the pop up window.
The pop up window will close and your table will be transparent. Click "Process Page Update" to save your work and you're done!