How to Make It
Bring a saucepan of lightly salted water to a boil. Add edamame and cook until soft but not mushy, 4 to 5 minutes. Drain and let cool slightly.
Pulse edamame, 2 Tbsp. olive oil, 1/2 tsp. salt, garlic, scallions and lemon juice in a food processor several times until coarsely pureed. Add water, a tablespoon at a time, until puree just comes together. Toss shrimp with 1 Tbsp. olive oil and lemon zest. Season with salt and pepper.
Place a rack 4 to 5 inches from heat source and preheat broiler. Brush bread slices with remaining 1 Tbsp. oil and sprinkle with salt. Spread in a single layer on a baking sheet. Broil until bread turns golden, watching carefully to prevent burning, 1 1/2 to 2 minutes. Flip bread and toast other side until lightly golden, another minute or so. Spread edamame mixture on oiled side of bread, top with shrimp and herbs, if desired, and serve.