Wash and dry all ingredients.
Thinly slice the onions and cucumbers. Quarter the plum tomatoes, then mince the garlic and set aside. Roughly chop the parsley.
To prepare the vinaigrette, mix the lemon juice, parsley, and garlic in a bowl. Slowly add the olive oil, whisking vigorously to combine. Season to taste with salt and pepper.
To serve, toss the cucumbers, tomatoes, onions, and chickpeas with the vinaigrette.
Store in an airtight container in the fridge for up to 5-7 days.