Citrus and fresh herbs add clean, fresh flavor to the salmon, so you don't need to use much (if any) salt. Cilantro lends zing here as well.
Heat grill or grill pan to medium-high. In a medium bowl, combine orange segments, avocado, red onion, cilantro, lime juice, and sesame oil. Season to taste with salt and pepper and set aside.
Season salmon and bok choy with salt and pepper and drizzle with olive oil.
Grill salmon, flipping halfway through, until cooked through, 3 to 4 minutes per side. Grill bok choy until bright green and slightly wilted, about 1 minute per side. Spoon avocado salsa over fish to serve.