Lightly coat asparagus spears with oil. Sprinkle with sea salt. Brush tuna with olive oil and sprinkle with salt and pepper.
Grill tuna for 2 to 2 ½ minutes per side. (The center should be raw.) Allow fish to rest while grilling asparagus for approximately 5 minutes. During grilling, roll spears 1/4 turn every minute to ensure even cooking.
Remove from grill and set aside.
For salad dressing
Add ingredients for dressing together in a small bowl and set aside.
In a large bowl add mesclun. Whisk salad dressing to combine and drizzle over greens.
Add grilled asparagus and hard cooked eggs. Sprinkle with sunflower seeds and freshly ground pepper. Top with tuna.