If air flow from the leading edge to the trailing edge stops, it is a stall. High aspect ratio wings such as used by the U-2 can stall (especially at high altitude), and low aspect ratio wings such as 747s and 990s can stall (especially at low speeds). The true delta (not found on the Concorde) can stall. Modified deltas or double deltas (Lockheed's specialty) are harder to stall but can indeed stall.
Books on the Convair B-58 Hustler can help probably more than most on that subject. Convair wrote the book on delta wing attributes. However, many others have stood on Convair's shoulders to find out more.