I agree with the above. I use browser tabs like favourites, I have 7 tabs open in the stock browser and another 5 open in chrome.
If I've finished with a site I'll close the window/tab but I leave the core ones there all the time.
I can't see any benefit to me in closing the browser completely.
Still if you really want to, all of the suggestions above work.
When I first got an android phone I would open a new tab with the homepage and close all the other tabs and then hit back... until I found out that there was no need.