Preheat oven broiler to high.
In a large bowl, combine shrimp marinade: 1 1/2 tbsp olive oil, chili sauce, Sriracha, zest and juice of 1 lime, cilantro, garlic and crushed red pepper flakes. Whisk to combine. Toss in shrimp and evenly coat with marinade. Set aside.
Heat 1 tsp olive oil in a large skillet over medium heat. Once hot, add diced pineapple. Cook for 8-10 minutes, flipping two or three times to caramelize all sides. Remove and let the pineapple slightly cool.
Prepare guacamole by removing fruit from avocados and placing in a large bowl. Use a fork to thoroughly mash avocado. Add diced red pepper, cilantro, lime juice, cooled pineapple, salt and pepper and stir to combine.
Using the same large skillet, return to medium-high heat. One hot, add shrimp and cook for ~2 minutes per side, until cooked through.
Brush bread slices evenly with remaining olive oil (~1 1/2 tbsp). Broil for 1-2 minutes on each side or until toasted.
Spread guacamole evenly on toasted bread slices. Distribute shrimps evenly (~3 per crostini). Crumble goat cheese evenly over top. Serve!