Many of the sparkling sakes available in the US (think Mio as an example) can be very much on the sweet side.
There are a number that are not, however.

My favorite sparkling is from Masumi in the Nagano region. The usual version you will find in the US is the Grand Prix version (with a price to match) but there is a "lesser" version that tastes just as good if you search for it.
The immediate visual difference you will see is that the Grand Prix version has a champagne style cork and cage while the other version has a metal bottle cap.

Fukucho also make a sparkling Junmai named Seaside which can also be very good and not so much on the sweet side. That can be found a little more readily in the states

Hope this helps