Rinse the radishes under cold water and pat them dry. Slice them thinly using a sharp knife or a mandoline for even pieces.

Cut the avocado in half, remove the pit, and scoop the flesh into a bowl. Dice it into bite-sized pieces and place them alongside the sliced radishes. If using cucumber, add it now.

In a small bowl, whisk together the lemon juice and olive oil. Drizzle it over the radishes and avocado, then sprinkle with salt and pepper to taste.

Gently toss everything together, being careful not to mash the avocado.

Garnish the salad with fresh herbs and optionally add halved cherry tomatoes.