Remove leaves from cauliflower head, core, and cut into bite-sized florets. Place cauliflower in provided resealable bag and pound with a medium pot until it resembles coarse pieces. Don't worry if some larger stem pieces remain. Trim ends off celery and cut into 1/4" dice. Trim and thinly slice green onions on an angle, keeping white and green portions separate. Zest and halve lemon. Cut one half into two wedges and juice other half. Rinse tilapia fillets, pat dry, and season both sides with half the Cajun seasoning (reserve remaining for cauliflower).

Place medium pot over medium heat. Add 2 tsp. olive oil, celery, and white portions of green onions to hot pot and cook 4-6 minutes, stirring occasionally, or until vegetables are tender and slightly browned.

Add cauliflower, half the remaining Cajun seasoning, and tomato juice to pot and cook 14-16 minutes, stirring occasionally, or until cauliflower is tender and tomato juice has reduced to a sauce that clings to vegetables. Taste, and add remaining Cajun seasoning and a pinch of salt and pepper if desired. Cajun seasoning already contains salt and pepper. While "jambalaya" cooks, begin tilapia.

Place a large non-stick pan over medium-high heat. Alternatively, cook in two batches using a medium non-stick pan. Add 2 tsp. olive oil and tilapia fillets to hot pan and cook 3-5 minutes per side, or until browned and fish reaches a minimum internal temperature of 145 degrees.

Combine Thousand Island dressing, 2 tsp. lemon juice, 1 tsp. lemon zest, green portions of green onions (reserve a pinch for garnish), and capers in a small bowl.

Place a serving of cauliflower "jambalaya" on a plate. Place a tilapia filet next to jambalaya and spoon remoulade over fish. Garnish with reserved green onions and a lemon wedge.