Fill the Multi-Function Cooker with 4 quarts (3.8 liters) warm water. Place the Sous Vide Rack in the Multi-Function Cooker. Set the Multi-Function Cooker to Sous Vide Mode and set the temperature to 120°F (49°C). Press Start.
Make the lime compound butter:
In the work bowl of a food processor, combine butter, green onion,garlic, lime zest, and salt. Pulse until smooth. Transfer mixture to a piece of plastic wrap. Shape into a log and wrap in plastic wrap. Freeze until ready to use.
Make the salmon:
Sprinkle salmon with salt and pepper. Place 1 salmon fillet and 1 tablespoon (14 grams) lime compound butter in each of 4 (1-quart) heat-safe bags. Seal the bags but do not vacuum completely. (75% vacuum is desirable for fish.)
Make the asparagus:
Divide asparagus, dill, oil and salt between 2 (1-quart) heat-safe bags. Seal the bags and vacuum lightly. (25% vacuum is desirable.)
When the water reaches the set temperature, add the salmon and asparagus pouches to the water bath. Cover and press Start. Cook for 20-30 minutes for medium. Adjust temperature if more rare or more well-done is desired for either salmon or asparagus. When finished cooking, remove the pouches from the water bath. Remove asparagus and salmon from the pouches. Discard the water and wipe the Multi-Function Cooker clean.
Set the Multi-Function Cooker to Sauté/Sear Mode, HIGH and press Start. Add oil. Pat salmon dry with paper towels. When oil begins to shimmer, add salmon to the Multi-Function Cooker, skin side down. Sear until skin is crispy and browned, 1-2 minutes. Turn salmon, and sear until browned, 1 minute more. Serve salmon and asparagus with remaining lime compound butter.