I did not know this feature was even there until I read the article at one of my favorite sites (I Love Free Software). Yes, you can now send secure, self-destructing emails in Gmail using what is called confidential mode. I encourage you to learn how to use this feature by following the tutorial that is provided by clicking on the source link below.
This tutorial explains how to send secure and self destructing emails in Gmail using confidential mode. This is a new feature of Gmail which has come with its new interface. While composing an email in Gmail, you can turn on confidential mode in a single click. After that, you can set expiration time of the email using the preset options (expire in 1 day, 3 months, 1 week, 1 month, or 5 years). Apart from that, it also provides passcode feature to securely send that particular self destructing email.