In a small heat-proof bowl, whisk together the Greek yogurt, one egg yolk, lemon juice, and Dijon mustard until perfectly smooth.
Place the bowl over a pot of barely simmering water (double boiler style) and whisk constantly for 3-5 minutes until the sauce is warm and thickened; do not let it boil or the yogurt will curdle.
Remove the sauce from heat and stir in the sea salt, black pepper, and cayenne pepper, then set aside in a warm spot.
Fill a medium saucepan with water, add the white vinegar, and bring to a very gentle simmer.
Crack the two poaching eggs into separate small ramekins, then carefully slide them into the simmering water.
Poach the eggs for exactly 3 minutes for a firm white and liquid gold yolk, then remove with a slotted spoon and drain on a paper towel.
While the eggs poach, split and toast the English muffin and lightly sear the Canadian bacon in a dry skillet over medium heat until browned.
Assemble by placing two slices of bacon on each muffin half, topping each with a poached egg, and drizzling with the warm zesty hollandaise.
Garnish with freshly chopped chives and serve immediately.