Preheat the oven to 450°F and line a baking sheet with parchment paper. Slice the sweet potatoes in half lengthwise. Slice each half into 5-6 wedges. Add sweet potatoes to a medium sized bowl with two tbsp. oil and 1/2 tsp of salt. Toss to coat. Lay potatoes in a single layer on the parchment-lined baking sheet and bake for 10 minutes.
Rinse and dry green beans and snap off ends. In a small bowl, whisk together mustard, lemon juice and remaining olive oil.Take a second piece of parchment, about 15 inches long, fold in half and then unfold. In the center of one half, layer about 8-10 green beans and sprinkle with salt.
Place the salmon fillet on top of beans, sprinkle with remaining salt and pepper, and spoon on 2 tbsp. mustard sauce.
Fold parchment back over to cover salmon. Starting at the right hand crease, fold the parchment over itself to create a small triangle. Fold that piece over itself and continue folding got create small pleats all the way around the parchment. When you’re done, you should have a half-moon or ‘calzone’ shape.
Take out the potato wedges; push them to the perimeter of the baking sheet. Place parchment packet in the middle. Lower heat to 400°F and bake packet for another 10 minute. Remove from oven, slice through the packet- it’s ready! Top with Dijon sauce.