Combine wine, onions, bay leaves, stock, salt, and pepper in a pan and heat for 20 minutes without simmering.
Boil the potatoes with salt and mint in a separate pan for 20-25 minutes until tender.
Add salmon fillets skin-side down to the poaching liquid, cover with foil, and poach on low heat for 10 minutes.
Add asparagus to the poaching liquid, cover, and poach for another 5 minutes until tender.
Heat the butter in a pan over medium heat until foaming vigorously.
Blend egg yolks, mustard, and lemon juice in a food processor until pale.
Slowly pour the hot butter into the running food processor until the sauce thickens.
Season the hollandaise sauce with salt and pepper in a bowl.
Serve the salmon with potatoes and asparagus and drizzle with the hollandaise sauce.