In a soup pot, heat the oil over medium heat. Add onions and cook until golden brown and slightly carmelized. Whisk in the flour until it is a nice golden colour, about 2-3 minutes. Add the Cajun seasoning and whisk about 30 seconds. While whisking, stream in the clam juice until the mixture is smooth and golden brown. Add the tomatoes and their juice and gently stir them in with a wooden spoon. Heat until bubbling and then reduce heat to low and simmer for 3-4 minutes. Stir in thyme and garlic. Remove from heat and add spinach. Stir until spinach has just wilted and gently stir in the crab meat. You can either serve the soup immediately as a chowder with some crusty bread, or chill and enjoy cold the next day as a gaspacho. Granish with a sprig of fresh thyme Either way, it is Yummers! Enjoy!