Cook manicotti noodles in a large pot of salted, boiling water until al dente. Meanwhile, cook Rice-A-Roni according to package directions until done. Next, saute garlic and onions in lightly oiled skillet over medium heat until onions are transparent, about 3-4 minutes. Mix in drained beans and corn with rice, season with cayenne pepper, garlic salt and lime juice, and cook until warmed. In a 9x13 baking dish, stuff manicotti noodles with cooked rice/bean mixture using a spoon (similar to filling a penny or dime roll) and lay side by side (you will probably have extra bean mixture left over as a few of the noodles break). Spoon taco sauce over stuffed noodles and bake at 350F for 35 minutes, or until thoroughly warmed. Garnish with green salsa, scallions and rice sour cream and serve.
Note: A mixture of wild and white rice cooked with a variety of favorite seasonings would suffice for the Rice-A-Roni; its simply much faster to use a packaged rice mixture.