Preheat oven to 375°F. Line a baking sheet with parchment paper.
Chop salmon finely or pulse in a food processor until coarsely ground.
In a bowl, mix salmon with breadcrumbs, egg, green onions, lemon juice, garlic powder, salt, and pepper.
Form mixture into small balls and place on the baking sheet.
Bake for 18–20 minutes until golden and cooked through.
While the salmon balls bake, mash avocado in a bowl, then stir in Greek yogurt, lime juice, cayenne, and salt.
Serve salmon balls warm with creamy avocado sauce for dipping.