I bought this leafy green at H-Mart, a Korean supermarket. It was labelled "Monchoy", but I can't find anything online for that term! Both raw and sautéed, it has a slimy texture reminiscent of okra, and I'd like to figure out how it's typically cooked. What is this vegetable usually called, and what part of the world does it come from?
Although it's hard to say without seeing the stalks, your description of the flavor and texture is consistent with Malabar Spinach, also called Wood Ear. It's used in a variety of Asian and African cuisines.