Dice the potatoes into bite-sized pieces (if using new potatoes, which are very small, you may not need to chop them).
In a large pot, add salted water and potatoes and bring to a boil; boil until cooked and easily pierced with a fork. When done, drain the potatoes and rinse them under cold water to cool.
Meanwhile, cut the ends off of the snap peas, and finely mince the shallot. Mince the dill and rosemary (or other fresh herbs).
In a large bowl, mix together the snap peas and shallot with Greek yogurt, whole grain mustard, garlic powder, kosher salt, fresh ground pepper, dill and rosemary until combined. Then mix in the potatoes and stir until everything is coated. Serve room temperature or cold.