Can I create a report of sales with tax on my site?

There is a reports area you can access from menu commands Tools > Report Writer in your account.
Choose New Report > Order Items Level Summary:
On the Report Settings tab, give the report a name and set the columns you want in the report. Under Report Structure > Select Columns you can enable various colums of information about the report. OrderTax and OrderTotal are two of the colums that can be enabled.
Note that the interval and time settings are only available if you have Pressero Professional or Enterprise.
Under Allowed Groups tab, check the admin user groups that should have access to the report. If its not restricted, then just check all of them.
Then under Selected Sites, check the site(s) that the report should pull data from.
Go back to the Report Settings tab and hit Run Report. The report settings will be saved and you will go back out to the Report Writer window.
The Report Writer window does not automatically reload right now when waiting for a report. When your report is ready its status will say Success, it will say Executing while it is being run, or may say Failed if something was wrong. But clicking Tools > Report Writer will reload that page while you are waiting.
The report can then be downloaded from the right side of the listed reports: