In a bowl, mix the shrimp with olive oil, chili powder, cumin, salt, and pepper. Let it marinate for about 15 minutes to absorb the flavors.

Heat a skillet over medium-high heat. Add the marinated shrimp and cook for about 3-4 minutes until they turn pink and are cooked through.

Warm the taco shells in the oven for a few minutes. Once ready, fill each shell with cooked shrimp.

In a bowl, dice the avocado, tomato, and onion. Add lime juice and chopped cilantro. Mix gently to combine and then spoon the salsa over the shrimp-filled tacos.

Serve the tacos with a squeeze of lime and fresh cilantro garnished on top. Store any leftovers in an airtight container in the refrigerator for up to two days, and consider adding fresh toppings before serving.