Slice the avocados in half and remove the pit.
Scoop the flesh into a bowl and dice it into cubes.
Dice the cucumber and bell pepper, and add them to the bowl.
Thinly slice the red onion and add it to the mixture.
Halve the cherry tomatoes and toss them in.
In a small bowl, whisk together olive oil and lemon juice.
Season the salad with salt and pepper to taste.
Pour the dressing over the salad and gently toss to combine.
Chop fresh herbs and sprinkle them over the top.
Crumble feta cheese over the salad before serving, if desired.