Why are you wondering about the sesame oil? Are the special dishes you are referring to the Oriental dishes, like Chinese, Japanese, Korean, and many others, and if so, that is the toasted variety, you add at the end, usually, as a flavoring oil; also, in many dip sauces, for that delicious flavor. It is dark, in color, and shouldn't have other oils added to it, which I have seen before, especially in "Hot Sesame Oil" for that, just make your own. Mixed oils with it go rancid quickly, unless kept refrigerated.
For the other sesame oil - the light colored - sometimes you'll find it labeled "Raw Sesame Oil", and it's often found in health food is. That is better kept refrigerated, as it can also go rancid quicker. It's can take higher heat than the toasted, but not as high as the highly refined sesame oil. The refined oil is what they mean if you see them call for sesame oil in Indian recipes, and it's used for the everyday cooking, in some areas.