First make the jalapeno sauce. Put all the ingredients in a bowl with a tsp salt and plenty of black pepper. Mix well and leave to let the flavours develop.
Cook the fish fingers in the oven according to the packet instructions.
Meanwhile heat the olive oil in a large frying pan and add the onion and red pepper. Cook over a medium high heat until they start to brown around the edges but still have some bite.
Add the garlic, cumin and chipotle paste followed by the lime zest and juice. Stir and continue cooking for a few more minutes.
Remove the fish fingers from the oven and roughly break them up. Add them to the pan and gently toss everything together.
Pile the fish fingers and vegetables onto warm tortillas and dress with the jalapeno sauce. Sprinkle with any of the garnishes and squeeze over some lime juice before eating.