Place the sliced red onions in a small bowl and cover them with cold water (this helps remove some of the onions’ harsh bite).
In a small bowl or large measuring cup, whisk together the dressing ingredients: Lime juice, olive oil, honey, garlic, salt, and pepper.
In a very large bowl, place the cucumbers, tomatoes, avocado, half of the feta, and cilantro. Drain the red onion, then add it to the bowl. Pour the dressing over the top, then stir very gently to combine. Sprinkle the remaining feta over the top. Enjoy immediately or cover the bowl with plastic wrap and refrigerate for up to 4 hours. Give the mixture a gentle stir just before serving.
Notes
TO STORE: Store leftovers in the refrigerator for up to 1 day. The avocado will brown slightly and the vegetables will become more liquidy, but the salad will still taste delicious.