Steps
1. Heat olive oil in a small pan over medium heat.
2. Sauté the sliced onions until translucent and slightly caramelized, about 4-5 minutes.
3. If using frozen corn, briefly sauté or microwave until warm.
4. In a bowl, combine the cooked rice, sautéed onions, corn, and drained tuna.
5. Gently fold in the diced avocado and lime juice.
6. Season with salt and pepper to taste.
7. Garnish with chopped cilantro if desired and serve immediately.