On a touch device, double click is indeed a double tap. Another alternative is a long tap: double tap is used by several applications (such as Chrome and Google Photos) for zooming.
Both double click and double tap presents a few problems which make them a questionable design choice:
Discoverability. How do I know that I need to click/tap the element twice? What happens if I do it only once?
Accessibility. Some users may not be able to click/tap fast enough. In Windows, the double click duration can be configured, but getting the value right isn't easy. Set it too short, and you won't be able to double click. Set it too long, and you'll be getting too many false positives.
Distinction with other interactions. Two clicks or taps at the edge of an interactive element may lead to false positives out negatives. If elements are small, this could become an important issue.
Instead of relying on a double tap, imagine a way you could make the interaction area without it.
Example: Windows file explorer
In Windows, a click on a file selects it. A double click opens it.
GMail had a similar problem: a user may want to open an e-mail, or just select it. However, Google solved this case much more effectively. A tap on an e-mail opens it: makes sense, since this is what most users do most of the time. A long tap selects the e-mail without opening it. This, however, presents a problem of discoverability. On PC, users also have checkboxes for each e-mail in the list; on mobile devices, this was replaced by the photos of senders which can be used to quickly select one or several e-mails without using the long tap; here again, discoverability is an issue.