Prepare the dressing: Combine garlic, oregano, salt, balsamic vinegar, and olive oil in a jar. Secure the lid tightly and shake vigorously to emulsify. Allow it to rest for at least 20 minutes for the flavors to infuse.
Prepare the salad: Cut tomatoes into wedges and then into bite-sized pieces. Slice cucumber into ½ cm (1/5 inch) thick slices. Peel and finely slice the red onion. Cut bell pepper into short strips. Cube the feta cheese into 1 cm (2/5 inch) cubes.
Combine and Serve: Place tomatoes, cucumber, onion, feta, and olives into a serving bowl. Sprinkle with dried oregano and pour the dressing evenly over the top. Gently toss the salad to combine all ingredients thoroughly.
Finish by adding freshly ground black pepper to taste. Serve immediately and enjoy your fresh, vibrant Greek salad!