It may be something of a stretch to call Tennyson's poem below "dactylic dimeter," though it certainly is some kind of two-beat meter. Of course, one could consider that the two beats were part of one foot, such as a choriamb ( / * * /), but that stretches things, too--even more, since some lines have as many as six syllables.

If we call it dactylic, though, we have to allow for the omission of final unstressed syllables through catalexis in most lines, but at least most lines begin with a definite dactyl. In marking where the catalexis occurs, implied offbeats have been added.
 

                         Minnie and Winnie   [ / * * | / * (*) ]
                                 Slept in a shell.    [/ * * | / (*) (*)]
                            Sleep, little ladies!
                                 And they slept well.

                            Pink was the shell within,
                                 Silver without;
                            Sounds of the great sea
                                 Wander'd about.

                            Sleep, little ladies!
                                 Wake not soon!
                            Echo on echo
                                 Dies to the moon.

                            Two bright stars
                                 Peep'd into the shell.
                            "What are you dreaming of?
                                 Who can tell?"

                            Started a green linnet
                                 Out of the croft;
                            Wake, little ladies,
                                 The sun is aloft!
 

Some lines of Tennyson's "Charge of the Light Brigade" seem to work well when scanned as dactylic dimeter:

                            /    *   * |  /     *  *
                        Cannon to right of them,
                        Cannon to left of them,
                        Cannon in front of them
                        Volleyed and thundered