Preheat the oven to 400 degrees. Wrap sweet potatoes in foil and place in the oven for 1 hour.
Meanwhile, to make the cashew sour cream. Combine cashews, water, mustard and lemon juice in a high speed blender.
Make the salsa by combining the beans, corn, cumin, lime, onion and cilantro.
Once the potatoes can be pierced easily with a knife remove them from the oven. Slice the potato down the middle and pry open a bit. Load the inside of the sweet potato with 1/2 cup of salsa, followed by 1/2 C of guacamole and then top with cashew sour cream.
These potatoes will keep in the fridge for 2 days.