Prepare the cucumber: Wash and slice the cucumber thinly. You can keep the peel on.
Dice the avocado: Cut the avocados in half, remove the pits, scoop out the flesh, and dice.
Slice the onion: Peel and thinly slice the red onion. You can soak it in cold water for 5–10 minutes to reduce sharpness.
Chop the dill: Rinse and finely chop the fresh dill.
Mix the dressing: In a small bowl, whisk together lime juice, olive oil, a pinch of salt, and pepper.
Toss everything: In a large bowl, gently mix cucumber, avocado, red onion, and dill. Pour the dressing over and toss lightly to coat.
Serve immediately: Serve fresh for the best taste and texture. Optional: chill for 10–15 minutes before serving.