Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Peel and dice the carrots and beets into half-inch cubes, then toss them on the baking sheet with half of the olive oil, sea salt, and black pepper.
Roast the vegetables for 25 to 30 minutes, tossing halfway through, until they are tender and slightly caramelized.
While the vegetables roast, season the chicken breast with the remaining salt and pepper and sear in a skillet over medium-high heat for 6 to 7 minutes per side until fully cooked.
Remove the chicken from the pan, let it rest for 5 minutes, then slice it into thin strips.
Place the chopped kale in a large mixing bowl and drizzle with the remaining olive oil and lemon juice, massaging the leaves with your hands for 2 minutes until they become dark green and tender.
Add the roasted carrots, beets, and sliced chicken to the bowl with the kale.
Roughly chop the fresh mint and cilantro and fold them into the salad just before serving to maintain their bright flavor.