It is fairly straightforward on a soprano, even with small hands. All it takes is practice. On a tenor, it is another story. It is really quite tricky. Someone with small hands is going to find it almost impossible in that position. If you move further up the fingerboard though, to say 7 7 6 10, it becomes much easier. However, you then get a chord of Gm.
The question is: why do you want to play this Dm chord? It is hard to play (on any uke) and is not needed very often. A similar sounding Dm chord is 2 5 5 5. This is a bit easier to play (1st finger on 2nd fret, 4th finger on 5 fret). Try it.