Heat a large skillet over medium heat. Add the oil, and when it is hot, add the onions, carrots, and cumin.
Sauté them for 3 – 5 minutes until the onions are tender and just starting to brown.
Wash and add the greens while they are still wet (if they are dry add 1/4 cup of water) and the salt, cover, and reduce the heat as necessary to steam the greens for 10 minutes or until they are tender.
Uncover the pan, add the vinegar, and sauté for another 1 - 2 minutes, and serve.