In a small bowl, whisk lime juice, lime zest, 2 tablespoons olive oil, honey, 1/4 teaspoon salt and 1/4 teaspoon pepper until dressing holds together.
In a large sauté pan, heat remaining oil over medium-high heat.
Season salmon with remaining salt and pepper. Sear for 3 minutes each side.
Meanwhile, rinse and chop lettuce and place on a serving platter.
Layer lettuce with grapefruit and avocado. Place cooked salmon on top and garnish with green onions.
Drizzle dressing over top and serve.