Preheat your oven to 400°F and line a small baking sheet with parchment paper.
Toss the cherry tomatoes with half of the olive oil, sea salt, and black pepper on the prepared sheet.
Roast the tomatoes for 12 to 15 minutes until the skins are blistered and bursting.
While the tomatoes roast, fluff the pre-cooked quinoa and set it aside to reach room temperature.
Drain the sardines and place them in a non-stick skillet over medium heat with the remaining olive oil, minced garlic, and dried oregano.
Sear the sardines gently for 2 minutes per side until warmed through and fragrant.
Arrange the chopped romaine lettuce on a large platter as the base.
Top the lettuce with the quinoa and the warm roasted tomatoes, ensuring you drizzle any tomato juices from the pan over the greens.
Place the seared sardines on top and finish the platter with a bright squeeze of fresh lemon juice.