Depends on how big you want your pinwheels. Two easy solutions are to cut out squares the same size you have. Put right sides together. Then you can either sew around the perimeter then cut the block twice from corner to corner. You will end up with 4 two-tone triangles that you can sew into pinwheels. Or, draw a line down the middle of one of the squares and sew a seam 1/4 inch on each side of the line. Then cut on the line to have two larger two-tone triangles. Repeat with another square and you will have 4 triangles that you can use for a pinwheel.
Hope that made some sense to you.
Rereading your question, I guess you don't want to use the squares you have in the pinwheels, so ignore what I wrote. The previous response was probably better. Make a bigger pinwheel and cut it down to the size you need.