If you want to display K2 items purely as a table, first you need to make sure that you only display the item elements you need in a K2 category. E.g. the title, introtext, image and/or extra fields. If you just want the extra fields and the item title, just select to show these 2 elements from the related category's settings.
After that, if you want to actually display your K2 items in a table, you need to do some K2 template overriding or perhaps apply custom CSS via your template to enforce the new look. For detailed info on K2 template overriding, have a look here:
getk2.org/documentation/tutorials/174-templating-with-k2-and-the-concepts-of-sub-templates 
