To make Hollandaise sauce, fill bottom of double-boiler part-way with water; make sure water does not touch top pan. Bring water to a simmer.
In top of the double-boiler, whisk together egg yolks, lemon juice, and 1 tablespoon water.
Add butter to egg yolk mixture 1 or 2 tablespoons at a time, whisking constantly. If sauce becomes too thick, add 1 to 2 teaspoons hot water. Whisk until butter is incorporated.
Whisk in salt, and sriracha; remove from heat and cover.
To poach eggs, fill large saucepan with 3 inches of water.
Bring water to a gentle simmer, add vinegar.
Carefully break eggs into the simmering water and cook 2 1/2 to 3 minutes or until whites are cooked and yolks are still soft in center, then remove the eggs with a slotted spoon and set on warm plate.
In a medium skillet, cook SPAM® Classic over medium-high heat 3 to 4 minutes or until lightly crisp.
Place English muffins, cut-side-up, on serving plates.
Top evenly with avocado, tomato, SPAM® Classic, and poached egg. Drizzle with Hollandaise sauce. Sprinkle with cilantro and red pepper, if desired. Serve immediately.