You can do this 2 ways, firstly if you want to totally get rid of those sections, under Admin-> Features turn off the Top and Bottom sections.
If you want to replace them with your own text (for the top) and remove the text but leave/change the buttons (for the bottom) then turn on the Edit Templates feature in Admin->Features
Next example the Admin Menu and choose the Edit Templates
Choose either tiki-top_bar.tpl or tiki-bot_bar.tpl and click on its name, this will change to a text editing window, where you can use HTML to format what you want.
Hope it helps, if you have trouble, or want more details message me or post back