Bulfleet.com - Official Forums

1. top right options
2. click on the planet you want to delete
3. wait for an e-mail with a code
4. then input the code and save changes

Deletion is permanent! also make sure you demolish all buildings there
and move all resourses and ships away.

As far as I know, they will be randomized the next time. How many fields your colony will have is decided when you create your colony. Here is some info on colonizing and planet fields. http://www.bulfleet.org/viewtopic.php?t=24311

One thing that post doesn't remind you is to take resources with you. I don't have the exact numbers, but if you take about 5,500 metal and 2,000 crystal, you will be able to build your new colony up very quickly, without waiting for the mines to produce.