01 - Combine lentils, water, and bay leaf in a medium saucepan. Bring to a boil over high heat, then reduce heat to low and simmer uncovered for 18–22 minutes until lentils are tender but retain their shape. Drain thoroughly, discard bay leaf, and let cool slightly.
02 - While lentils simmer, finely dice red onion, carrot, and celery. Halve cherry tomatoes and coarsely chop fresh parsley and chives. Keep prepared vegetables separate until assembly.
03 - Whisk together olive oil, red wine vinegar, Dijon mustard, honey, minced garlic, lemon zest, lemon juice, and a pinch of salt and pepper in a small bowl until fully emulsified and slightly thickened.
04 - Transfer warm lentils to a large serving bowl. Add diced onion, carrot, celery, cherry tomatoes, parsley, and chives. Pour vinaigrette over the mixture and fold gently to evenly distribute dressing without crushing lentils.
05 - Taste salad and adjust seasoning with additional salt, pepper, or lemon juice as needed. Serve immediately while warm, let stand at room temperature for 20 minutes, or refrigerate and serve chilled.