Cook the potatoes: Add the potatoes to a large saucepan and cover with water. Place over medium-high heat and bring to a boil until potatoes are cooked, about 10 minutes. Drain and set aside to cool.
Meanwhile, massage the kale: Place kale into your serving bowl and add 2 tablespoons of pesto. Massage the leaves until dark green and tender, approximately 2 minutes.
Mix, dress, and serve the salad: Add the potatoes, cucumber, red onion and tomatoes to the kale. Add the remaining pesto and lemon juice. Season with a pinch of salt and pepper. Toss until the dressing is evenly distributed. Taste and adjust seasoning and lemon juice to your preference. Serve.