Preheat oven to 425°. Oil a large rimmed baking sheet and line with parchment paper, then oil paper lightly. Lay salmon, skinned side down, on sheet. Whisk together remaining salmon ingredients. Slather onto salmon and marinate at least 20 minutes (chilled, up to 1 1/2 hours). Roast until just firm, 12 to 20 minutes.
Meanwhile, heat olive oil in a large frying pan over medium-high heat. Add onions and peppers and cook, stirring, until just softened, 5 minutes. Remove from heat and stir in 1 1/2 cups of dill.
Put noodles in a serving bowl. Arrange herbs on a platter. Set noodles, herbs, sauces, and rice papers on the table, leaving room for 2 or 3 wide, shallow bowls of hot water for dipping rice papers.
Carefully loosen salmon from parchment with a thin spatula. Lift parchment with salmon, wide end closest to you, and tilt salmon onto a large platter (it will slide off easily). Arrange vegetables alongside salmon. Sprinkle salmon with remaining dill sprigs and crushed peanuts. Set on the table, along with bowls of hot water for dipping rice papers.
To make spring rolls, quickly dip a rice paper in hot water to barely soften, then layer with small amounts of vegetables, herbs, noodles, and salmon. Roll up in wrapper. (For a how-to illustration, watch Dao layer, fold, and roll at sunset.com/springrollvideo.) Dip rolls into sauces. Or build your own noodle bowl with same ingredients, drizzle with sauces, and top with crackers if you like.
Make ahead: Noodles, up to 1 day, chilled. Sauces, up to 1 week, chilled.
Note: Nutritional analysis is per noodle bowl.
Nutritional analysis per spring roll: Calories 662 (46% from fat); Protein 53g; Fat 34g (sat 1g); Carb 38g; Fiber 2g; Sodium 795mg; Chol 38mg
Wine pairing: Toulouse 2014 Valley Foothills Vineyard Gewürztraminer (Anderson Valley; $24).