1. Prepare the hollandaise sauce: In a bowl, whisk egg yolks and lemon juice until thickened. Place over simmering water and slowly add melted butter, whisking constantly. Add cayenne pepper and salt to taste. Keep warm.
2. Cook the asparagus: In a skillet, cook asparagus in boiling water until tender, about 3-4 minutes. Remove and set aside.
3. Cook the Canadian bacon: In the same skillet, cook Canadian bacon until browned, about 2-3 minutes per side. Set aside.
4. Poach the eggs: In a saucepan, bring water to a simmer. Crack eggs into the water and cook until whites are set but yolks are still runny, about 3-4 minutes. Remove with a slotted spoon.
5. Assemble: Place toasted English muffin halves on plates. Top each with a slice of Canadian bacon, a poached egg, and a few asparagus spears. Spoon hollandaise sauce over the top and serve immediately.