Blanch the tomatoes in boiling salted water for 30 seconds. Remove tomatoes and shock them in an ice bath. Peel tomatoes, reserving 1/2 of 1 of the tomatoes. Dice the reserved tomato and set aside.
Using a blender or food processor, puree the tomatoes, the celery and the cucumber until mixture has reached a liquid. Strain puree through a fine mesh strainer. Season to taste with salt, pepper, cayenne, extra-virgin olive oil, honey, and hot red pepper sauce. Chill finished tomato soup until cold.
In a small to medium sized mixing bowl whisk together the mustard, vinegar, salt, pepper, and grapeseed oil. Add the tuna, the reserved diced tomatoes, capers, shallots, parsley, and chives, mixing all ingredients together. Taste for seasoning, and adjust if necessary. Set aside in a cold place. Using 4 small chilled bowls, place equal sized towers of Ahi tartar in the center of each bowl. Whisk or blend the chilled soup and pour about 2 ounces of soup around the tower of tartar, garnish with a sprig of parsley or caviar. Serve.