If I have an audio speaker signal that is rated for 1 Watt @ 32 Ohms, is it safe to wire a 1W/8 Ohm speaker with a 24 Ohm resistor on one of the speaker leads?
SIGNAL SOURCE ------|24 Ohm Resistor|-----SPEAKER +
SIGNAL SOURCE ------------------------------SPEAKER -
If your source can drive a 32 ohm load and you connect it to a 32 ohm load it will be OK.
The best way how to connect the 8ohm speaker to 32ohm output is via an audio transformer with 2:1 winding ratio, thus you will not loose 2/3 of your power there.. 
Or if it's a square wave output, build a little buffer amplifier using a transistor. A 2N2222 would do a fine job.