For the sauce: Combine the mayonnaise, mustard, 1 tablespoon warm water, lemon juice and cayenne pepper in a blender and process until combined. Scrape out and set aside.
For the eggs: Fill a wide pot with about 3 inches of water. And the vinegar and bring to a low simmer.
Meanwhile, heat the oil in a large nonstick skillet. Add the Canadian bacon and shallots and cook, stirring frequently, until golden, about 4 minutes. Add the kale, remove from the heat and stir until the kale wilts, about 2 minutes. Season with pepper. Set aside and keep warm.
Toast the English muffins in a toaster oven or under a broiler until lightly golden, about 5 minutes. Top each with a tomato slice and toast until the tomato is just slightly warm, about 1 minute. Top each tomato slice with the Canadian bacon-kale mixture.
Crack each egg into a separate mug or bowl, and slip them one at a time into the simmering water. Cook until the whites are at desired doneness, 3 to 5 minutes. Remove with a slotted spoon and place on each English muffin. Drizzle with the hollandaise. Serve each with 1/2 cup of berries and a glass of milk.