In a mixing bowl, finely chop hard-boiled eggs and combine with shredded mozzarella cheese, mayonnaise, Sriracha, chopped chives, kosher salt, and black pepper. Mix well and set aside.

Heat a nonstick skillet over medium-high heat and lightly spray with olive or avocado oil.

Scoop about 1/4 cup of the egg salad mixture into the skillet and flatten into a cake. Cook for 1 to 2 minutes until golden brown, then flip and cook for an additional minute.

Toast the bread until golden. Spread avocado on top, place the crispy egg salad cakes on it, and garnish with jalapeño slices. Serve immediately.