You can delete multiple transactions at once from your computer by logging into the web app at https://web.hurdlr.com/login.
Navigate to the Income or Expenses page where you want to delete your transactions. Check the boxes next to the transactions you want to delete, or use the select-all feature to highlight all of your transactions on that page, then click the "Trash" icon at the top. You may delete up to 50 transactions (1 page of 50 rows) at a time.