Preheat oven to 400˚F. Line a baking sheet with parchment paper.
In a medium bowl, whisk to combine yogurt, water, 1 tbsp. oil, lemon juice and ¼ tsp. salt. Stir in the parsley and dill and refrigerate until ready to use.
In a small bowl, combine 1 tbsp. oil, mustard and ½ tsp. salt. Place salmon fillets skin side down on prepared baking sheet, and brush fillets with mustard mixture. Bake until cooked through and fish flakes easily with fork, about 12-15 minutes.
While salmon bakes prepare asparagus by filling a large saucepan with about 1 inch of water. Place in a steamer basket in the pan, bring water to a boil, and then add asparagus to the steamer basket. Cover and steam for 4-5 minutes until crisp tender.
Lay out tortillas on a clean work surface and layer each with salmon fillet, asparagus, snow peas and onion. Top with yogurt sauce, fold in one end and then roll tightly to create wrap.