Shrimp tacos with avocado purée and sweet & sour sauce

For the shrimp:

250 g shrimp, peeled 1 tsp paprika 1 tsp garlic powder 2 tbsp olive oil Salt pepper

For the avocado purée:

2 ripe avocados 1 tbsp olive oil Juice of 1 lemon Salt pepper

For the sweet & sour sauce:

100 g sugar 150 ml water 80 ml white vinegar 50 ml soy sauce 1 tbsp corn flour 2 tbsp ketchup

To serve:

4 small tortillas (or 2 medium) 1/2 iceberg lettuce, shredded