Wash the cucumber thoroughly and slice it into thin rounds or half-moons, depending on your preference.
In a large bowl, combine the sliced cucumber and salt. Toss gently to coat the cucumber slices evenly. Let them sit for about 10 minutes to draw out excess moisture.
After 10 minutes, drain any excess liquid from the bowl.
Add lime juice, chili powder, garlic powder, and cilantro (if using) to the cucumber slices. Toss everything together until the cucumbers are well coated.
If desired, sprinkle crumbled queso fresco on top before serving.
Serve immediately or chill in the refrigerator for 15-30 minutes for a refreshing snack.