Is there a way to gift an application from the Mac App Store as you can with the iOS App Store?

No. Unlike with the App Store on your iOS device or in iTunes you won't find a Gift This App link on the Mac App Store. What I suggest you do instead is to launch iTunes, click the iTunes Store link, and then click the Buy iTunes Gifts link on the store's home page. On the resulting iTunes Gifts page click the Buy Now link in the Email Gift Certificates area, purchase a gift certificate that covers the cost of the application you want to gift, and then issue the gift certificate to the object of your affection.

Then open the Mac App Store, select the application you want to send as a gift, and from the price pull-down menu choose Tell a Friend. In the Tell a Friend window that appears, enter the giftee's email address and in the Message field enter a message that strongly hints that you'd like that gift certificate to be used for the purchase of this application.