Peel and halve the cucumber, scrape out the seeds. Cut into small cubes. Heat 1 tablespoon butter in a soup pot, sweat the cucumber pieces in it. Pour in the chicken stock, let it stand for about 10 minutes. Fish out 4 tablespoon cucumber pieces, puree the rest in the pot. Put the cucumber pieces back, add the cream, season with lemon juice, curry and possibly salt. Cut the salmon into fine strips. Briefly add to the soup, let simmer. Divide the soup into 4 soup cups, decorate with dill.