Directions
1 Place the Russet potato pieces into a large saucepan,
   and cover with salted water. Bring to a boil, turn the
   heat down, and simmer for 10 minutes. Add the sweet potato,
   and cook about 15 minutes more. Remove a piece of each
   potato, and cut it in half to see if it is cooked enough. Once
   the potatoes are tender, add corn kernels; cook another 30
   seconds. Drain through a colander. Fill the saucepan with cold
   water, and drop vegetables into water. Cool for 5 minutes,
   and drain.
2 In a large bowl, whisk together mustard, lime juice,
   cilantro, and garlic. Slowly whisk in oil. Mix in salt and
   black pepper.
3 Cut cooled potatoes into 1 inch cubes, and add to
   dressing along with cucumber, and red onion. Toss well. Serve
   at room temperature or chilled. Toss the peanuts in just
   before serving.