Preheat oven to 400ºF. Rub the ears of corn with olive oil and season with salt. Roast on a baking sheet until corn is tender, about 25 minutes. Cut the kernels off the corn cob and add to a medium mixing bowl.
Add the jicama, jalapeño, onion, cilantro and lime juice to the bowl and stir to combine. Season with salt to taste and refrigerate until ready to use.
For the fish:
In a small mixing bowl whisk together paprika, chipotle chili powder, garlic powder, onion powder, cayenne and salt. Season the fish with the mix on both sides.
Heat a large sauté pan or grill pan over medium heat, add olive oil and heat through. Add the fish and cook until completely cooked through and flakey, about 6 minutes depending on thickness.
For serving:
Bring the rice and 2½ cups water to a boil over medium heat. Once boiling, cover the pot and reduce the heat to medium-low. Cook until all the water has been absorbed and the rice is tender.
Divide the rice among 4 bowls. Top each with some of the shredded cabbage, tomato, jicama salsa, sour cream, queso fresco, and a piece of fish. Serve immediately.