For the halibut, mix the flour, cayenne pepper, celery salt and garlic powder in a bowl and season well with salt and freshly ground black pepper. Dredge the halibut steaks in the spiced flour mixture and shake off anty excess.
Heat the oil in a pan over a medium heat. Add the butter, and when it begins to foam add the fish.
Cook the halibut steaks for three minutes on each side, or until just cooked through. (If the steaks are very thick, transfer them to the oven preheated to 180C/365F/Gas 4 and roast for a further 4-6 minutes, or until completely cooked through.)
For the bean salad, whisk the tomato juice, red wine vinegar, olive oil and garlic together in a bowl. Season, to taste, with salt and freshly ground black pepper, then add the mixed beans, celery and chilli and mix well.
For the tzatziki, mix the yoghurt, dill and lime juice together in a clean bowl.
Add the grated cucumber and season, to taste, with salt and freshly ground black pepper. (Thin the mixture down with water if necessary.)
To serve, place a large spoonful of the bean salad into each serving bowl. Place a piece of halibut on top of each and spoon a dollop of tzatziki alongside.
Garnish with lime wedges and chopped parsley and serve.