In a small bowl, mix together the flour and black pepper.
Dredge the cube steaks in the flour mixture, shaking off any excess.
Heat the olive oil in a large skillet over medium-high heat. Once the oil is hot, add the cube steaks and brown on both sides, about 2-3 minutes per side.
While the cube steaks are browning, add the sliced onion to the crock pot.
Once the cube steaks are browned, transfer them to the crock pot, laying them on top of the onions.
In a separate bowl, mix together the cream of mushroom soup, dry onion soup mix, beef broth, Worcestershire sauce, and salt.
Pour the soup mixture over the cube steaks.
Cover the crock pot and cook on low for 6-8 hours, or until the cube steaks are tender and fully cooked.
Serve hot over rice, mashed potatoes, or with your favorite side dishes.