Take a look at this doc. It has the timing for the SPI read. Pages 24-26.
http://www.mouser.com/catalog/specsheets/steval-isv009v1.pdf
Notice on page 25 the 16 bit data is apparently returned with the NOP sends.
byte Readspanning = SPI.transfer(0x05); // read spanning
// this should be byte 1 (high byte)
byte Readspanning2 = SPI.transfer(0x01); // nop
// this should be byte 2 (low byte)
byte Readspanning3 = SPI.transfer(0x01); // nop
Then I would use the serial monitor to print all those values and see if they make sense to you.