Drain and chop tomatoes; reserve 1 1/2 cups juice for Tomato Gravy. Combine tomatoes, lamb, potatoes, onion, and salt; mix well. Shape into 2-inch patties; dredge in flour.
Heat vegetable oil in a large skillet; add lamb patties. Cook over medium heat until browned on one side; turn and brown other side. Transfer patties to a warm serving platter. Reserve 2 tablespoons pan drippings for Tomato Gravy. Serve lamb patties with Tomato Gravy.