In a large mixing bowl, add a generous handful of mixed greens as the base. Dice a ripe avocado and add it along with halved cherry tomatoes and sliced cucumber. Toss gently to combine.

Thinly slice a small red onion and add it to the salad mixture. Crumble feta cheese over the top while ensuring the ingredients remain distinct for vibrant presentation.

In a separate bowl, whisk together olive oil, lemon juice, salt, and pepper. Allow the dressing to sit for about one minute to meld the flavors.

Drizzle the dressing over the mixed ingredients, toss carefully to avoid bruising the avocado. The salad should remain bright and inviting.

Serve immediately, plating in bowls or on a platter. Enjoy the fresh salad as a light, refreshing meal.