Skyline does not have any sort of Signal to Noise column available in the document grid.
Skyline does calculate the "Background" when Skyline integrates peaks. You can see a diagram of how Background gets calculated here:
You can find the Total Area and Total Background columns under in the Customize Report dialog under:
Proteins > Peptides > Precursors > Precursor Results
There is no single column which would tell you the ratio of area to background. This is something you would need to calculate in another tool such as Microsoft Excel.
Skyline does not have the ability to specify that you have no enzyme. If you are studying intact proteins, you can add those proteins to your document using the menu item:
Edit > Insert > Peptides
Put the entire protein sequence in the "Peptide Sequence" column.