Whisk together the dressing ingredients in a small bowl: olive oil, lemon juice, garlic, sea salt, and black pepper until well blended.
Halve and slice the English cucumber and cherry tomatoes.
Drain and rinse the chickpeas under cold water.
Slice the medium red onion thinly.
In a large salad bowl, combine the chopped veggies, chickpeas, and sliced avocado. Add chopped cilantro.
Pour the prepared dressing over the salad ingredients and gently toss until everything is coated evenly.
Serve immediately or let it chill in the fridge for about half an hour before serving.