As APPSeCONNECT does not store any transactional data during the sync process, there is no way to delete any data from APPSeCONNECT. The sync and error log available in APPSeCONNECT can be deleted. However, it is suggested to keep all the data as a back-up with you.
The connection and configuration details of your old integration can be deleted from APPSeCONNECT. However, we recommend you to archive this in your cloud account.