Combine all ingredients in a bowl, then taste and adjust seasoning with salt and pepper as needed.
Refrigerate for at least 10 minutes to allow the flavors to meld together.
Cilantro Lime Rice:
Place the rice in a mesh strainer and rinse under cold water, until the water runs clear. Drain well and set aside.
In a medium saucepan with a lid, butter over medium heat. Once hot, add the rinsed rice and chopped onion. Stir frequently and cook until the rice turns from translucent to bright white and the onion softens.
Add the minced garlic and stir for about 30 seconds, just until fragrant but not browned.
Pour in the chicken stock. Add salt and stir, then reduce the heat to the low. Cover with a lid and let it cook for 15 minutes.
Remove the pan from heat and let it sit, still covered, for 10 minutes.
Once fully cooked, drizzle the lime juice over the rice and sprinkle with chopped cilantro. Use a fork to fluff the rice and mix in the lime juice and cilantro. Serve immediately
Salmon:
In a large mixing bowl, combine soy sauce, avocado oil, brown sugar, lime juice, garlic, and spices. Add the salmon fillets, turning them to coat evenly. Cover with plastic wrap and refrigerate for at least 20 minutes—or up to overnight—for maximum flavor.
When ready, lift the salmon from the marinade and let any excess drip off (discard the leftover liquid to prevent flare-ups on the grill).
Grill the fillets skin-side down for 7–9 minutes, turning once halfway through. If the grill marks darken too quickly before the center is cooked, return the salmon skin-side down. Cooking times vary by grill and heat, so check doneness with an instant-read thermometer: remove the fish when it registers 135–140 °F (it will continue to rise to about 145 °F as it rests).
Plate the salmon right away alongside mango salsa and cilantro-lime rice.