Mix mayonnaise and Sriracha in a small bowl, and set aside.
Fry eggs sunny side up over medium-low heat on the pan for 3-5 minutes, or until dark brown and crisp on the bottom.
Mix soy sauce, Thai sweet chili sauce, brown sugar, water in a small bowl, and set aside.
Slice spam into 8- ΒΌ inch pieces and pan fry in vegetable oil over medium heat. Fry both sides for 2-3 minutes each, or until golden brown and crisp. Remove fried spam and use paper towels to wipe excess oil from the pan.
Add spam back to the pan and pour sweet soy sauce over it. Simmer over medium-low heat for 2-3minutes, flipping multiple times.
When the sauce is reduced by a third, remove the pan from heat and let it cool for 2-3 minutes before assembling the sandwich.
Slice tomatoes and cut lettuce into sandwich sizes.
Toast 2 sliced bread for each person.
Place spam on top of one slice of bread, and then stack sliced tomatoes, lettuce, and fried eggs on top of it (in that order). Spread spicy mayo and leftover sweet soy sauce over the other slice of bread, and cover the sandwich.
Serve with a side of salad or fries. Enjoy!