There is no out of the box report for expense sheets. However, there are 3 options you can take to do what you ask.
You can go to Expense Sheets module and filter it by "submitted" and then just export it to Excel. This is the easiest way to achieve your goal.
You can wait till the end of this year when our new Reports module that will allow this.
You can use Clarizen Excel Add-in to do this as well.