Sometimes in restaurants, the pieces of veggies in a salad are cut kind of large. If this is the case and you cannot pick up some of your salad and eat gracefully, you can cut the piece with the edge of your fork, or use your fork and knife, but only to cut the piece you will be lifting to your mouth. Do not attack everything in the salad plate at one time.
A salad fork should be provided if the salad is served in a separate plate. If the salad is served on your entree plate, then eat the salad with your regular dinner fork.
If the main entree dish is a salad, such as Chef's Salad, don't try to pour all of the dressing over it and mix it in at one time. Pour a little dressing over a portion of your salad and eat that. Continue in this manner until the "pile" of salad on your plate is more manageable. Then mix the rest of the dressing in.
Another pet peeve I have when salad is served at a restaurant is when they use salad plates that are too small (more like dessert plates, actually) and then pile the salad on. This makes for a very ungraceful way to eat your salad, since most of the time you end up spilling food off your plate.