1. Click "Accounts" in the top right corner.
2. You will see a list of all of the accounts that have been added. Click the light gray arrow to the right of the bank (not the sub-account) you want to delete.
3. Click "Delete this institution"
4. That bank and all associated accounts will no longer be listed in your accounts window and will not import transactions any longer.
*This will not delete transactions already imported by this account. You'll need to delete those transactions manually.
5. If you don't want to remove your entire bank, but just one of the sub-accounts, click the arrow next to the sub-account. Then click "Delete this account".
Also if you would like to see the balance of this account but don't wish to import transactions from it, then simply uncheck the "Sync Transactions" button.