Preheat oven to 400°F and line a baking sheet with parchment paper.
Toss the asparagus spears, sliced red bell pepper, and red onion with half of the olive oil, sea salt, and black pepper.
Roast the vegetables for 12-15 minutes until they are tender and slightly charred around the edges.
While the vegetables roast, pat the shrimp and sea scallops dry with paper towels to ensure a golden sear.
Heat the remaining olive oil in a large skillet over medium-high heat and add the minced garlic.
Sear the scallops for 2 minutes per side and the shrimp for 1-2 minutes per side until they are opaque and cooked through.
In a large mixing bowl, whisk together the fresh lemon juice, dried oregano, and chopped fresh parsley.
Add the roasted vegetables and seared seafood to the bowl, tossing gently to coat everything in the lemon-herb dressing.
Divide the salad into bowls, top with fresh avocado slices, and serve immediately.