Wash the squash and place it on a cutting board; carefully cut it in half lengthwise using a sharp knife.
Scoop out and discard the seeds and stringy bits from each half with a spoon.
Place the squash halves cut-side down in a 9×13-inch microwave-safe glass dish; if your dish is smaller, use two 8×8-inch dishes or cook halves separately.
Pour about 1 cup water into the dish so there is roughly 1 inch of liquid; add more water if needed to reach that level.
Microwave on high for 10–15 minutes, testing after 10 minutes by piercing with a fork; total time depends on squash size and microwave wattage.
The squash is done when a fork easily pierces the skin and the flesh shreds into noodle-like strands.
Carefully remove the hot dish from the microwave, turn the squash halves cut-side up, and use a fork to shred the flesh into strands; season with kosher salt and black pepper to taste.
