Prepare brown rice on stove top or in rice cooker, adding beef bouillon to water.
While rice cooks, heat vegetable oil on high heat in a wok or large skillet. Add sliced zucchini and mustard greens; salt and pepper to taste. Sauté until zucchini begins to brown, being careful not to overcook the zucchini. Add soy sauce and continue to sauté until zucchini is tender. Add sliced sausage, garlic, beans, and Cajun seasoning to taste. Continue to sauté, adjusting heat as necessary, until the sausage is heated through.
When rice is cooked, add it to the wok and toss together.