Preheat the oven to 425ºF. Peel and slice the sweet potatoes into ½ inch wide sticks.
Toss the sweet potato sticks in a bowl with vegetable oil, chili powder, cumin, salt and pepper, then place on large baking sheet.
Roast the sweet potatoes in the oven for 20 minutes, flip and stir, and return to the oven. Roast for about 15 minutes more, or until the sweet potatoes are browned on the edges.
Take the potatoes out of the oven and top with cilantro, feta, salt and pepper. Squeeze 1 or 2 of the lime wedges on top, and drizzle with spicy olive oil. Serve with tomato chili sauce as a dip on the side (optional).
