01 - Combine rinsed lentils, water, bay leaf, and 1/2 teaspoon salt in a medium saucepan. Bring to a boil over high heat, then reduce heat and simmer uncovered for 20-25 minutes until lentils are tender but retain their shape. Drain through a strainer, discard bay leaf, and allow to cool slightly.
02 - In a large mixing bowl, combine the cooled cooked lentils, halved cherry tomatoes, diced cucumber, finely diced red onion, diced bell pepper, sliced Kalamata olives, and chopped fresh parsley.
03 - In a small bowl or mason jar, whisk together extra-virgin olive oil, fresh lemon juice, dried oregano, minced garlic, Dijon mustard, salt, and freshly ground black pepper until fully emulsified.
04 - Pour the prepared dressing over the lentil mixture and toss gently to evenly coat all ingredients without breaking the lentils.
05 - Add the crumbled feta cheese and toss lightly to distribute throughout. Taste and adjust seasoning with additional salt and pepper as needed.
06 - Serve immediately at room temperature, or cover and refrigerate for up to 2 hours to allow flavors to meld before serving.