The term "julienne" means “matchstick” and refers to vegetables cut into long, slender strips. Julienne is both a decorative technique and also makes denser vegetables cook more quickly. Cutting julienne vegetables by hand requires a steady hand and a lot of practice. Julienne green beans are especially tricky due to their size. Once you master the knife work involved, you can create delicate French-style julienne beans.
Rinse the green beans in cold water. Cut off and discard the stems.
Cut the beans in half, lengthwise. Put them in a bowl.
Lay one bean cut-side down, lengthwise. Curl your fingers and place the flat edge of your nails against the long edge of the bean. Curling your fingers allows you to hold the bean in place and avoid cutting your fingers.
Hold the knife at the base of the handle, where it meets the blade. Holding the knife lower gives you better control.
Place the tip of the knife on the farthest end of the bean, opposite your fingers. Rock the blade downward, along the length of the bean, as if using a paper cutter, to cut off a matchstick-width sliver of bean.
Repeat the cutting motion across the width of the bean, working toward the fingers on your opposite hand. Put the cut beans in a bowl of ice water.