Shrimp roll with red wine onion jam

Ingredients

• 2 red onions, thinly sliced
• 1/2 cup red wine vinegar
• 1/2 cup dry red wine
• 1/2 cup sugar
• 1/2 lemon, juiced
• 1/4 teaspoon salt
• 1/4 teaspoon black pepper
• 2 pounds shrimp, roasted and coarsely chopped
• 1 to 2 ounces lemon juice (juice of 1 lemon)
• 3/4 cup mayonnaise
• 1 tablespoon white wine vinegar
• 1 teaspoon Dijon mustard
• 1/2 teaspoon sugar
• 1/2 teaspoon salt
• 1/2 teaspoon black pepper
• 1 tablespoon parsley, minced
• 1 teaspoon capers, minced
• 1 teaspoon dill, minced
• 1 jalapeno, finely chopped
• 2 celery stalks, finely chopped
• 2 scallions, thinly chopped (whites and greens)
• 1 6-inch bread roll
• 1/4 to 1/2 cup shrimp and dressing
• 2 to 3 tablespoons red wine onion jam