Preheat oven to a low broil setting.
In a large bowl, add mayonnaise, lemon juice, mustard, celery, pickles, red onion, garlic, jalapeno, and parsley and mix to combine. Season with salt and pepper.
Using a fork or knife, chop up the Lightly Seasoned Jackfruit by The Jackfruit Company. Then add the jackfruit to mayonnaise mixture and mix to combine.
Toast the bread. Place bread on a baking sheet and top with one slice of cheese, spinach, a few tomato wedges, and a few avocado slices.
Divide the jackfruit “tuna” salad between the four slices of bread. Top each piece with another slice of cheese. Bake until cheese is melted; 5 minutes.
Enjoy!