To poach the eggs, add 3-inches of water to a high sided skillet and bring to a simmer over medium heat. Add the vinegar into the water and season with salt.
Crack one egg into the fine mesh sieve and gently jiggle it around a little to remove any runny egg white. Gently tip the egg into the water continue with the rest of the eggs. Poach the eggs for 3 to 4 minutes, carefully flipping halfway through. Remove the eggs to a piece of paper towel.
For the hollandaise, place a medium or large saucepan filled with 1- to 2-inches of water over medium heat and bring to a simmer. Melt the butter in a small saucepan over medium heat until bubbling. In a large heatproof bowl (preferably glass or ceramic), add the egg yolks, lemon juice, cayenne, and ¼ tsp of salt and whisk to combine.
Place the bowl over the simmering water and, while continuously whisking, slowly stream in the hot butter. Keep whisking until the hollandaise is thick and creamy then remove the bowl from the heat so that it doesn’t overcook. If the hollandaise seizes up at any point, splash in a few drops cool tap water until the sauce smooths out.
Split and toast the English muffins. If the eggs have cooled, dip them back into the hot poaching water for 10 to 20 seconds. If you need to reheat the hollandaise, simply place back over the simmering water and whisk until heated.
Top the English muffins with some ham or smoked salmon and a poached egg. Pour over the hollandaise and scatter with cayenne pepper and chives.
