Prepare the Dressing: In a small bowl, whisk together fresh lemon juice, minced garlic, salt, black pepper, and optional chili flakes. Slowly drizzle in extra-virgin olive oil, whisking until emulsified and smooth.

Cook the Lentils: Rinse the lentils under cold water, add to a medium pot with a bay leaf and enough water to cover by 2 inches. Bring to a boil, reduce heat and simmer for 20-25 minutes until tender. Drain excess water.

Combine Lentils and Dressing: Transfer warm lentils to a large mixing bowl, discard the bay leaf. Pour the dressing over and gently toss until coated. Allow to cool slightly.

Add Fresh Vegetables: Chop cucumber, bell peppers, and green onions. Add to lentil-dressing mixture along with chopped parsley and mint. Toss gently to combine.

Final Taste Adjustments and Serving: Taste and adjust seasoning if needed. Serve immediately at room temperature or refrigerate for up to 3 days.