Heat the olive oil in a medium saucepan over a medium heat, add the chilli and garlic. Moments later add the fennel and fry for several minutes until translucent and softened slightly. Add the tomatoes, parsley and some seasoning, bring to a simmer and cook for 25–30 minutes, stirring occasionally, until you have a thick sauce.
Heat a large non-stick frying pan over a high heat, season the salmon and briefly sear it, half at a time, to lightly colour on all sides. Gently fold the salmon and butter beans into the sauce, discarding any liquid given out by the fish, and transfer the mixture to a shallow ovenproof dish, approximately 20 x 30cm. The filling can be prepared a couple of hours in advance, in which case cover and set aside in a cool place.
For the crumble, whizz the pecans until finely chopped in a food processor, then add the ground almonds, oats, the butter and a little seasoning and briefly whizz until the crumbs start to hold together in nibs. This can also be made in advance, and chilled.
Preheat the oven to 210°C (fan 190°C/gas mark 6), scatter the crumble over the pie base and bake for about 30 minutes until the crumble is lightly golden. Serve scattered with extra parsley.