If only green beans tasted as good as the cactus at Rosa Linda's, kids would never have to be told to clean their plates. The kitchen here uses the nopales in tacos, in burritos, mixed in with lettuce and pico and other such adulterating flavors. But we like to pull the packages apart until we end up with a taco carcass on one side of the plate and a pile of cactus strips on the other, which we then eat with our fingers -- the way we still eat green beans when we can get away with it. But this cactus only tastes like green beans if you can imagine that vegetable as a fruit -- something dimly sweet, a little oily and vaguely astringent. It tastes like water in the desert -- which is what cactuses are, after all -- served in a restaurant that's been a refreshing oasis in northwest Denver for more than two decades now.