Place lentils in a medium size pot and add 2 cups of water. Bring to a boil. Reduce heat to medium-low and cook until tender, about 25 minutes. Drain excess water; mix in 1/4 tsp. of the salt and vinegar. Set aside to slightly cool.

While lentils cook, combine 2 Tbsp. of the olive oil, lemon juice, shallots, tahini, garlic, 1/4 tsp. salt, and 1/8 tsp. pepper in a small bowl; whisk to combine. Add 1 Tbsp. water and whisk until smooth. Let stand 10 minutes.

Place sweet potatoes and 3 Tbsp. water in a microwave-safe bowl; cover with plastic wrap. Microwave at HIGH 3 minutes or until tender. Pat dry with paper towels.

Heat remaining 2 tsp. olive oil in a large skillet over medium. Add potatoes, cumin, remaining 1/4 tsp. salt, and 1/8 tsp. black pepper; cook 6 to 7 minutes, until potatoes are golden-brown and crisp.

Combine kale, lentils, and sweet potatoes in a large bowl; toss to combine. (The kale should start to slightly wilt from the heat of the lentils and potatoes). Add tahini dressing, feta, and sunflower seeds. Mix well to combine. Add parsley or basil, if desired. Serve warm, chilled, or at room temperature.