First mix in a bowl the grated ginger, garlic, lime juice and zest and the chopped chili. Then, gently pour in the olive oil while whisking at the same time. Season the vinaigrette with salt, sugar and black pepper. Divide the vinaigrette into two bowls.
Add the chopped cilantro, radishes, avocado and the unpeeled shrimp to the first vinaigrette bowl.
In the other vinaigrette bowl, toss the arugula/rocket and the salad mix.
Next, spread some good quality mayonnaise on 2 slices of bread. Place some of the salad mix on the bread and the shrimp-avocado mix on top of the salad mix using a ring mould or a large spoonful.