Heat the Canadian bacon in the microwave or a skillet. Toast English muffins until lightly golden brown, spread with butter if desired. Hold both until eggs are poached
Fill a medium saucepan with 1-1/2 to 2 inches of water and 2 teaspoons of white vinegar. Bring water to a boil and then reduce heat to medium-low; water should maintain a few small occasional bubbles. Crack each egg into a small dish, partially submerge the dish into the pan, and tip the egg into the water, (or slide egg in gently). Cook until the whites are set and opaque, but yolks are still runny, about two minutes. Remove with a slotted spoon and drain on a paper towel. Trim any excess whites, if desired.
To make mock hollandaise, whisk the mayonnaise, Dijon, and lemon juice. Melt the butter and stir in quickly. Season with a pinch of salt and cayenne pepper. To assemble, top each muffin half with a handful of spinach, followed by a slice of tomato, a piece of Canadian bacon, and a poached egg. Drizzle with hollandaise sauce. Sprinkle with additional, salt, pepper and paprika. Serve immediately.