In a large mixing bowl, add the chopped cucumbers, bell peppers, and parsley. Stir to combine.
In a medium sized jar, combine the olive oil, vinegar, basil, salt, and pepper. Tighten the lid on the jar and shake vigorously for about 30 seconds, until the vinaigrette is well incorporated.
Spoon the vinaigrette over the salad until you reach your desired amount. If you have leftover vinaigrette, just store it in the pantry to use later.
Use a large spoon to stir the salad together until all of the vegetables are coated. You can eat it immediately, or let it sit in the fridge until ready to serve.