5 mini seedless or Persian cucumbers or 1 small English hothouse cucumber (about 12 oz.)
6 Tbsp. red wine vinegar, divided
1½ tsp. honey, divided
½ small red onion, thinly sliced
3 Tbsp. extra-virgin olive oil
Freshly ground black pepper
Gently smash cucumbers with a rolling pin or the back of a heavy knife just to break open. Tear into irregular 2″ pieces and place in a medium bowl; season lightly with salt. Let sit at least 5 minutes and up to 1 hour.
Meanwhile, mix 3 Tbsp. vinegar, 1 tsp. honey, a generous pinch of salt, and 3 Tbsp. water in a medium bowl to combine. Add onion and toss to coat. Let sit until softened, at least 5 minutes.
Whisk 3 Tbsp. oil, remaining 3 Tbsp. vinegar, and remaining ½ tsp. honey in a medium bowl to combine; season dressing with salt and pepper.