Most people will say no, nothing smaller than a 30 gallon for dwarf angels. I think it might be okay depending on the specific fish, your rockwork, and the other fish that you have. The fish will let you know by its behavior if that small of a tank is comfortable for them. Bottom line, you can either try it and see if it works in your situation or return the fish.
Lots of rock will help, not too many other fish will help too. Frequent feedings will likely be needed as the amount of live rock that will fit in that size tank will be quickly picked over. The pellets that I was talking about seem to keep them picking at the rocks in my tanks so that might help too. Good luck.