Pour brown rice and water into a small saucepan. Bring to a simmer over medium-high heat, then reduce heat to medium-low, cover, and simmer until rice is tender, about 40 minutes.

Preheat a skillet over medium-high heat. Add turkey sausage, and cook until well browned on the outside, and no longer pink on the inside. Remove cooked sausage, then stir in garlic and onion. Cook for a few minutes until the onion softens and begins to turn translucent. Add green pepper and cook for 2 minutes.

Pour in half of the vegetable stock along with the tomatoes and pimiento. Season to taste with red pepper flakes, Cajun seasoning, and pepper. Cook until the liquid has almost completely evaporated. Stir in sausage with remaining vegetable broth, and simmer until all is hot. Serve sausage mixture over brown rice.