I am using the default_ex template. These changes probably wont work for every Kunena template.
#fb_cat1 .td-1, #fb_cat1 .td-3 , #fb_cat1 .td-4, #fb_cat1 .td-5,#fb_cat1 .th-1, #fb_cat1 .th-3 , #fb_cat1 .th-4, #fb_cat1 .th-5, table#Kunena_top {display:none}
#fb_flattable .td-0, #fb_flattable .th-0 , #fb_flattable .td-2, #fb_flattable .th-2, #fb_flattable .td-6, #fb_flattable .th-6, #fb_flattable .td-7, #fb_flattable .th-7{display:none}
.fb-msgview-left, .fb-msgview-l-cover, .fb-msgview-left-b{display:none}
.fb_sth {display:none}
#Kunena div.fb_message_buttons_cover {float: left}