Place the shrimp in a large bowl and add the oil, lemon/lime juice and spices. Mix well to coat the shrimp in the spices and set aside.
Make the taco sauce by combining all the ingredients.
Cook the shrimp in a large, hot pan or griddle pan for 1-2 minutes per side or until cooked through and golden brown on both sides.
Assemble the tacos by topping warmed tortillas with shredded cabbage, sliced avocado, spicy shrimp and sour cream sauce. Finish with fresh coriander/cilantro and finely sliced chillies.