Pre heat grill to medium high heat.
Mix your spring onions with olive oil salt and pepper and grill (or grill pan) over medium high heat until charred, about 5 minutes. Set aside.
In a blender add everything for the romesco sauce except the olive oil. Blend until combined, then slowly drizzle in the olive oil while the blender is running until the sauce is a rich and creamy texture. Can be refrigerated for up to a week.
Slice avocado in half and remove pit. Peel off the skin. Slice the half very thinly. Set aside and cover with 1 tsp lemon juice to stop oxidization. Repeat with the rest of the avocados.
Drizzle olive oil over bread and toast on grill for two minutes a side until nice grill marks are achieved
To assemble spread a generous portion of romesco sauce over bread. Top with avocado and grilled onions. Dust with some paprika and an extra drizzle of olive oil.