Mix together the paprika, cumin, chilli powder and salt and pepper and rub over the salmon. Put the salmon under the grill (broiler) for 12 minutes, until cooked through.
Make the avocado cream by adding to a food processor the avocado, Greek yogurt, lime juice and water and blending until smooth. If you don't have a food processor, then you can mash it all together in a bowl, but you won't get as smooth a sauce.
Once the salmon is cooked, use a fork to flake it.
Build your tacos by lettuce mix to the soft tacos, top with the salmon, tomatoes and feta and then spoon over the avocado cream.
If you don't have a food processor, then you can mash the sauce ingredients together in a bowl, but you won't get as smooth a sauce.
If you are making these for younger children, then use less chilli powder (or leave it out) and leave out the salt.
Add some extra crunch by topping the tacos with slices of radish.
We used crumbled feta on top of these tacos, but you can use queso fresco to keep it more traditional if you can find it.
If salmon isn't your thing, then you could swap it for cod, or even some king prawns.
Use a lettuce leaf instead of a taco to save some calories.