Yes, for promotions that are hidden from the menu, and only available if a coupon code is inserted, you may use a link (that is sent to the food clients via some other channel, such as email or SMS). Here is how to create such link:
1. create the promotion in the restaurant admin panel, hide it from the menu, create a custom coupon code, and make sure the promotion is enabled.
2. open the website where the menu is published from a mobile device, open the menu, click on the link at the top of the page and copy the full link. For instance, open www.pronto-ny.com from a phone, and copy the menu link:
3. At the end of the link, add &coupon= and then the actual coupon code you set for the promotion.
In the above example, add &coupon=COUPONEXAMPLE, like this:
The promotion will be visible then in the menu and the food client can use it (presuming it fulfills all the other promo conditions).
Note: the promo link will always open in a new page.