I cut mine in half, scrape out the seeds and them place face down in a casserole dish. I poke the top a few times, add a tbsp of water, cover with saran wrap and microwave 7-9 minutes.
To make cutting easier sometimes I will just poke a few holes and nuke it whole for 2 minutes.
Serving size of 1 cup is only 42 calories. Half of my 8 inch squash was only about 120 calories and it was way to much for my lunch.