Wash all the vegetables thoroughly under cold water.
In a large salad bowl, combine the mixed greens.
Add the halved cherry tomatoes to the bowl.
Dice the cucumber and bell pepper, then add them to the mix.
Thinly slice the red onion and sprinkle it over the salad.
Chop the fresh basil and add it for flavor.
If using, crumble the feta cheese on top of the salad.
In a small bowl, whisk together olive oil and balsamic vinegar.
Drizzle the dressing over the salad and toss gently to combine.
Season with salt and pepper to taste before serving.