Slice the fennel thinly, preferably using a mandolin. Place it in a bowl of ice cold water immediately. This will make it extra crispy and crunchy. Let sit for a few minutes.
Preheat a nonstick pan over medium heat.
Add the cashew nuts and dry roast until golden brown, stir a few times. Keep an eye on them to make sure they don't burn. Set aside.
Place cut Romain lettuce, cucumber and avocado in a bowl.
Peel and segment the grapefruit, add to the bowl.
Peel and slice the mango, add to the bowl.
Drain the fennel well from the water together with smoked salmon, sliced spring onion and red chili.
Top with cashew nuts, cilantro and furikake seasoning.