In a small bowl, whisk together 1 cup of salt, ¼ cup of sugar, and ¼ cup of dill. Thoroughly coat the salmon on both sides with the salt mixture. Tightly wrap in plastic or place in a plastic bag. The salmon will release lots of liquid.
Place the wrapped salmon between two baking sheets and stack heavy items on top. Refrigerate for three days, or until most of the salt has dissolved and the salmon has compressed to about a half inch in thickness.
Remove the salmon and scrape off as much of the remaining salt and dill as possible. Thinly slice the salmon into strips approximately one inch long.
Cut the cream cheese into ¼ inch cubes. Wrap the salmon strips around the cream cheese cubes and then place them in a croustade.
In a separate bowl, whisk together the mustard, remaining dill, sugar, and vinegar until fully combined. Drizzle this mustard sauce over the croustades. If desired, garnish with cherry tomatoes and fresh dill.