Hi André
SMTP is very simple and I don't have a tutorial specifically for it.
You can follow the Kinetis tutorial at http://www.utasker.com/docs/KINETIS/uTaskerV1.4_Kinetis.pdf which explains the web server control pages. If you enable USE_SMTP in config.h it will then include the mail support and you can send an email on the start page:

This uses either hard-coded settings:
#define OUR_USER_DOMAIN "my_domain.com";
#define DEFAULT_DESTINATION_EMAIL_ADDRESS {'t','e','s','t','_','n','a','m','e','@','t','e','s','t','.','c','o','m',0};
#define SMTP_PROVIDER_IP_ADDRESS { 194,158,229,11 }
#define SMTP_PROVIDER_ADDRESS "mail.provider.com"
#define USE_SMTP_AUTHENTICATION
or you can enable parameters with
#define SMTP_PARAMETERS
and set them up dynamically on the SMTP page.
You can test in the uTasker K64 simulator and set break-point in the SMTP file to get to get to know any additional details as required.
Regards
Mark