Wash cucumbers and strawberries thoroughly. Slice cucumbers into thin half-moons and hull and quarter strawberries.

Slice red onion thinly and soak in cold water for 10 minutes if desired.

Roughly chop fresh mint leaves.

In a separate bowl, combine Greek yogurt, apple cider vinegar, honey, poppy seeds, salt, and pepper, whisking until incorporated.

Slowly drizzle olive oil while whisking to emulsify the dressing.

Combine cucumbers, strawberries, soaked red onion, crumbled feta, and chopped mint in a large mixing bowl. Sprinkle with red pepper flakes and gently toss.

Pour the dressing over the salad just before serving to maintain freshness and gently toss.