Thinly slice the chile(s) and combine in a small bowl with the vinegar.
Peel the squash and chop into thin-as-possible matchsticks. (I like to do this by cutting the top part into rounds, stacking those, and julienning. Then you can halve the bottom part, scoop out the seeds, and julienne from there.) Add the squash matchsticks to a large bowl and season generously with salt.
Halve, pit, and slice the dates. Add to the butternut squash, along with the chiles and vinegar. Break apart the feta with your fingers and sprinkle on top. Drizzle with oil (I eyeball a couple tablespoons) and toss. Adjust the salt, vinegar, and oil as needed.
Transfer to a serving platter if that’s your thing.