How to Make It
Place potatoes in a saucepan; cover with cold water to 2 inches above potatoes. Add 1 tablespoon vinegar. Bring to a boil; reduce heat, and simmer 10 minutes or until tender. Drain; let stand 10 minutes.
Combine basil, parsley, 1 ounce cheese, yogurt, mayonnaise, sunflower seeds, remaining 1 tablespoon vinegar, 1 tablespoon water, 1 1/2 teaspoons juice, salt, and garlic in the bowl of a food processor. Pulse 8 to 10 times or until smooth. Place potatoes in a medium bowl. Add pesto; toss to coat.
Combine remaining 1 teaspoon lemon juice and oil in a medium bowl, stirring with a whisk. Add arugula, tomatoes, and remaining 5 ounce cheese; toss to coat. Place about 1/2 cup salad on each of 6 plates. Top each salad with 1/2 cup potato mixture. Sprinkle with dill.