Preheat the oven to 350°F. Line a baking sheet with aluminum foil, and spray it with nonstick spray.
Place the salmon the baking sheet and smear the butter over the top. Season with salt and pepper. Bake for about 12 to 15 minutes, until just cooked through. Let cool on the baking sheet. Remove the skin from the filets if applicable.
Place the arugula in a large serving bowl. Peel and dice the avocado. Add the avocado and olives to the bowl. In a small container, combine the lemon juice, rice vinegar, olive oil, salt and pepper, shallots and jalapenos. Shake to blend, pour most of the dressing on the salad, and toss to combine. Flake the salmon into bit sized chunks and distribute them over the salad. Drizzle the remaining dressing over the salmon, give it a light final toss, and serve.
To roast jalapenos, preheat the oven to 350°F, toss the jalapenos to coat with olive oil, sprinkle with salt, spread on a rimmed baking sheet and roast them for about 1 1/2 hours until wrinkly and slight collapsed. Turn off the oven and just let them continue to soften as the oven cools. Seed and chop and use in recipes like this one.