How to Make It
In a small bowl, cover the onion slices with ice water and let stand for 10 minutes. Drain the onion.
In a large bowl, combine the garlic and vinegar. Whisking constantly, drizzle in the olive oil. Season with salt and pepper. Add the bell pepper, cucumber, basil, mint, dill and onion and toss to coat. Let marinate for 15 minutes, stirring occasionally. Add the tomatoes and toss gently; season with salt and pepper. Transfer the salad to a platter, top with the feta and serve.