Cut the avocado into small 1 cm slices, cut the cherry tomatoes in half, and cut the feta into medium cubes.
Season the lettuce with olive oil, salt and oregano. Mix gently.
Place the lettuce on a serving platter. Top with avocado and cherry tomato halves. Top with feta and red onion.
Sprinkle the salad with the juice of half a lime and serve.