Fill a small pot of water large enough to hold all the string beans. Add a pinch of salt to it. Bring to a boil.
While the water heats up, add the thinly sliced shallot to a small bowl, add the sherry vinegar and season with salt and pepper. Give it a stir and let this sit while you work on the beans.
Fill another bowl large enough to hold the string beans with water and a handful of ice to make a nice ice bath for the string beans when they are done cooking.
When the pot of water comes to a boil, add the green beans and blanch for 3 to 4 minutes until they slightly soften and turn bright green. When done, carefully strain the beans and quickly add them to the ice bath to stop the cooking and to retain the brilliant color. When they are completely cooled off, strain them again and dry them with a kitchen towel. Wipe dry the ice water bath bowl and transfer the green beans into the bowl. Add the marinated sliced shallots including the marinating liquid to the string beans. Add the chopped almonds and a drizzle of olive oil.
Taste and adjust seasonings with salt and pepper.