Preheat oven to 425°F.
Using sharp knife, cut both ends off plantains. Cut shallow slit down long seam of plantains, cutting only as deep as peel. Brush plantains with oil and arrange on parchment paper–lined baking sheet.
Bake, turning halfway, for 20 to 25 minutes or until golden brown and tender enough to pierce with a fork.
Meanwhile, in medium bowl, stir together rice, black beans, refried beans and cotija cheese until blended.
Let plantains cool slightly and remove peel completely. Cut a slit, lengthwise, down curved side of each plantain, being careful not to cut all the way through. Using 2 forks, gently pull each plantain open to form a “canoe” shape. Using flat side of fork, press down on plantain to widen the canoe for filling. Transfer back to baking sheet and season with salt.
Evenly stuff each plantain canoe with rice mixture, dividing evenly. Bake for 12 to 15 minutes or until filling is heated through.
Sprinkle with tomato and cilantro. Serve with lime wedges.
Alternatively, serve stuffed plantains with drizzle of sour cream and chopped avocado.