1) Cook Lentils: Fill 2 qt saucepan halfway with water. Add lentils and garlic, bring to a boil, reduce heat to a simmer. Cook uncovered until lentils are tender but not mushy (15-20 min.) Drain, remove and discard garlic, cool lentils to room temperature.
2) Make Dressing: In a small bowl, whisk together vinegars, mustard, dill, salt, and pepper (to taste). Slowly add oil, whisking constantly. Set aside. (You can make this a day ahead. Cover and refrigerate, but bring to room temp before using.)
3) Mix With Salad: In a medium bowl, mix lentils with green onions, carrot, celery, and cucumber. Gently mix in dressing. Adjust taste with a little salt as necessary. Let sit for 15-60 min at room temp. Garnish individual servings with goat cheese and fresh dill sprigs.
From Jen Johnson (adapted from The Oregonian)