Salad tongs are used for tossing salads to coat the ingredients in dressing.
You use the tongs to grab a bunch of leaves at the side of the salad mixing bowl, drag the bunch to the middle to pick up salad dressing, then flip the bunch over and drop it, and repeat for all sides of the bowl until all salad leaves are coated in the dressing.
The same salad tongs can then be used for serving.
They are usually made of plastic, silver or chrome plated metal, or wood. They often come as part of a matching salad set.
Be sure to use a generously-sized bowl that allows enough space to actually toss the salad. Generally, you want a bowl that is double the volume of the salad you are making.