[SamBam]

This is exactly the problem on Firefox on Android (don't know about iOs).

You tap on the address bar and are presented with a set of icons of your most-visited sites. Hitting any icon will open the site in a new tab. But it's not obvious, and it's easy for your tabs to balloon.

To prevent that you actually have to start typing the site name in the address bar, even if the shortcut icon is right in front of you.

In Chrome if you tap on the address bar you also get a set of icons, but clicking on one opens the link in the same tab, as you'd expect.