On most tablets, a long press of the bookmark will bring up either a menu that lets you delete the bookmark or a trashcan you can drag and drop it into. A better way I've found is an app called Bookmark Sort & Backup that can delete bookmarks and sort all your bookmarks as well.
Different browser have different options for deleting bookmarks. The most common would be a long press on the bookmark but in some brpwser, (actually most) it's possible to delete all the bookmarks at once. If you are syncing bookmarks from Chrome on a desktop to Chrome on your tablet you have total control. Same if you use Firefox on both.