Preheat the oven to 400 degrees and line a baking sheet with foil. Spray with cooking spray.
Toss the sweet potatoes with the olive oil, chili powder, garlic powder, and salt and pepper to taste. Pour the mixture on the baking sheet. Roast for 20-25 minutes until the potatoes are tender. Allow to cool enough to touch. You don't want the potatoes to completely wilt the arugula.
Whisk the red wine vinegar, olive oil, lemon and salt, and pepper together for the dressing.
Toss the arugula, sweet potato and lentils in your preferred amount of dressing. Place on a plate and top with the pomegranate and feta.