I have the same issue, the shortcut to show emojis dont work, but i found this solution: http://www.appletorchard.com/macos-emojis-in-adobe-xd-2-minute-tutorial/

This used to be possible with Mac OS emoji keyboard, but it was removed in a recent version :(

• Steps To Reproduce: Open an XD file on a Mac and, within a text box, press control + command + space
• Expected Result: The Mac OS Emoji & Symbols keyboard appears
• Actual Result: Nothing (except the 'I-beam' cursor disappears until it's moved)

From what I can see emoji support is there. I was able to add emoji no problems when manually invoking the "Emoji & Symbols" keyboard. However, what doesn't seem to be working (on Mac anyway) is the keyboard shortcut to display the emoji keyboard: control + Command + Space.

Not sure if this is specifically what you had in mind... but support for the macOS Character Viewer would be awesome. Also important for other symbols, more than just emoji:

https://support.apple.com/en-us/HT201586

+1 on the emoji-part :)

[Roughly translated: In the emoji font, the spaces get changed to an em-space after saving.]

最初、文字間のスペースを全角スペースで確定し、
その後、半角スペースに修正して編集を確定すると
全角スペースになって適用されることがある。

フォント：apple color emoji
サイズ：15 regulaar