You can press Ctrl+N to open a new window, but the new window loads with your home page. What I’ve found myself wanting to do is to open a copy of the current page in a new window. The way I figured was to click History in the menu bar and then Shift+Click to load the page on the top of the list (assuming the page you want is actually on the top of the list… if that’s not what you want keep looking down the list!).