Rub tilapia generously in Cajun spices. Marinate zucchini, onion, tomato, ketchup, olive oil, herbs and garlic.
Mix in bowl: olive oil Dijon mustard, brown sugar, balsamic vinegar, and salt and pepper.
Pour over vegetables and herbs.
In bowl: mix capers, Dijon mustard, paprika, jalapeño, Old Bay, and pinch of Cajun spice.
In hot cast iron pan, sear tilapia for two minutes on both sides.
Grill vegetables.
Mix mustard, vinegar, onion, tomatoes and peppers.
Julianne grilled vegetables and toss in balsamic vinegar; place vegetables on plate top with tilapia and creole tartar.