Rinse the French green lentils under cold water and place them in a medium saucepan. Add four cups of water or stock, a bay leaf, and a smashed garlic clove. Bring to a boil, then simmer for 20-25 minutes until tender. Add fine sea salt during the last 5 minutes, then drain and set aside.

Preheat your oven to 400°F (200°C). In a cold skillet, place the duck leg confit skin-side down. Render the fat for about 8-10 minutes until golden and crispy. Flip the duck, then roast for 10-12 minutes. Shred the meat, keeping skin in larger pieces.

In a small bowl, combine Dijon mustard, whole grain mustard (if using), red wine vinegar, honey, and a pinch of flaky sea salt. Whisk together and gradually drizzle in olive oil until emulsified. Adjust seasoning to taste.

In a large bowl, gently toss warm lentils with vinaigrette. Add diced celery, carrot, parsley, and chives. Mix gently, allowing lentils to absorb the vinaigrette flavor.

On a large plate, spread a bed of baby arugula. Layer warm lentil mixture on top, sprinkle crispy duck pieces, and top with walnuts and chèvre. Drizzle remaining vinaigrette on top and serve warm.