In a large skillet or cast iron pan, heat 1 tablespoon of olive oil over medium heat. Add the julienned onions with a pinch of salt and pepper, sauté for 5-7 minutes until softened and slightly browned. Add the bell peppers and sauté for an additional 5 minutes.

In the same skillet, add the remaining tablespoon of olive oil over medium-high heat. Add the shrimp and sprinkle half of the taco seasoning on top. Sauté for 3-5 minutes, flipping halfway through, until the shrimp are pink and opaque.

Return the sautéed vegetables back to the skillet with the shrimp. Squeeze fresh lime juice over the mixture and toss gently to coat everything in the seasoning. Heat for another minute.

Plate your shrimp fajitas, topped with fresh cilantro. Serve warm with tortillas, rice, or lettuce cups, and add toppings like diced tomatoes, avocado, or a dollop of sour cream.