Prepare the hollandaise by whisking the single egg yolk, Greek yogurt, lemon juice, sea salt, and cayenne pepper in a small bowl until completely smooth.
Place the bowl over a small pot of simmering water (double boiler method) and whisk constantly over low heat for 3-5 minutes until the sauce thickens; remove from heat immediately to prevent curdling.
Split the whole grain English muffin and toast until the edges are golden and crisp.
In a non-stick skillet over medium heat, sear the Canadian bacon for approximately 2 minutes per side until warmed through and lightly browned.
Fill a medium saucepan with water and the white vinegar, bringing it to a very gentle simmer.
Crack the remaining two eggs into separate small cups, then swirl the simmering water and gently drop the eggs in to poach for 3 minutes until the whites are opaque but the yolks remain soft.
Place two slices of Canadian bacon on each toasted muffin half, then use a slotted spoon to top each with a poached egg.
Generously spoon the warm yogurt hollandaise over the eggs and finish with a sprinkle of fresh chives and black pepper.