Drain pineapple juice into a 2-cup measuring cup and add water to make 2 cups liquid. In a saucepan, bring pineapple juice to a boil and dissolve jello. Cool slightly while you prepare the rest of the salad.
In a large mixing bowl, whisk together mayonnaise and evaporated milk. In a separate bowl, combine pineapple, cottage cheese, walnuts, and celery if desired.
Once jello has cooled, add to mayonnaise mixture. Then add the rest of the ingredients and stir to combine. Pour into an 8x8-inch pan and refrigerate until solidified, approximately 4 hours or overnight.
Cut into squares and serve on lettuce cups. Garnish with extra walnuts if desired. Alternately, scoop into sherbet bowls top with sweetened whipped cream and maraschino cherries.