Fill a medium saucepan with water and add the white vinegar; bring to a very gentle simmer over medium heat.
In a small heat-proof glass bowl, whisk the single egg yolk, Greek yogurt, melted grass-fed butter, lemon juice, and cayenne pepper until completely smooth.
Place the bowl over the pot of simmering water, ensuring the bottom doesn't touch the water, and whisk constantly for 3-5 minutes until the hollandaise thickens into a velvety sauce.
In a separate skillet over medium-high heat, lightly sear the Canadian bacon slices for 1 minute per side until warmed through and slightly browned.
Split and toast the whole wheat English muffin until the edges are golden and crisp.
Crack each of the two eggs into separate small ramekins, create a gentle whirlpool in the simmering water with a spoon, and carefully drop the eggs in to poach for exactly 3 minutes.
Place two slices of Canadian bacon on each toasted muffin half and carefully top each with a drained poached egg.
Generously drizzle the warm yogurt hollandaise over the eggs and garnish with sea salt, black pepper, and finely chopped fresh chives.