how can i dimension between two views?

currently not possible.

if this is an assembly, an alternate position view may get you what you want.

2017 SOLIDWORKS Help - Alternate Position View

Does it make sense to you for doing this?

I'm curious about why you'd need to, but in any case the only way I know of is to place some sketch geometry, restrained by relations to each view, and dimension to it.

Is this what you are looking for? Top view and front view with a dimension between them?

Do you want to drive the dimension or do you want it to be driven? I

f you want the dimension to be the driving number for the spacing and who wouldn't?

Draw a line from one view and drag it into the other view making sure no relation is established with the part in the second view. If there is a relation established delete it prior to dimensioning the line. Put your dimension in and establish a relation with the end of the line with the part in the second view.

Using layers and sketches will get you this kind of result, (A sketch in drawings can extend beyond one views boundary and have relations to another view).

Add some layers that you can turn off and you can hide the sketch as  well.

Does it make sense, break all rules of dimensioning.