Preheat the oven to 450F or 425F convection (use convection if you have it). Line a rimmed baking sheet with parchment paper. Add the sweet potatoes, olive oil and 1 teaspoon salt and toss to coat. Bake for 20 minutes, or until nicely browned/charred.
In a large bowl, add the lentils, kale, fennel, lemon juice and remaining ½ tsp salt and toss to coat.
To make the tahini dressing, add all ingredients to a medium bowl and whisk thoroughly to combine. You can also make this in a blender. If too thick, add more water or lemon. If too thin, add more tahini. This will depend on how thin or thick your tahini is.
Place the lentil fennel mixture on your plate and top with the roasted sweet potatoes, tahini dressing, toasted nuts, dill, and a squeeze of lemon. Sprinkle with salt and black pepper.