1. Heat a small saucepan over medium-high heat. Add 1 teaspoon canola oil to pan; swirl to coat. Add rice and 1/2 teaspoon garlic; sauté for 1 minute, stirring constantly. Add 2/3 cup water and 1/8 teaspoon salt; bring to a boil. Cover, reduce heat, and simmer 15 minutes. Remove from heat; let stand for 10 minutes. Fluff with a fork; stir in jalapeño.
2. Combine sour cream, chopped cilantro, juice, and red pepper in a small bowl.
3. Heat a large nonstick skillet over medium-high heat. Add the remaining 1 tablespoon oil to pan; swirl to coat. Add onion; sauté 2 minutes, stirring frequently. Add remaining 1/2 teaspoon garlic and mushrooms; sauté 1 minute, stirring frequently. Add corn and zucchini; sauté 2 minutes, stirring frequently. Add remaining 1/8 teaspoon salt and tomatoes; sauté 30 seconds or until tomatoes are thoroughly heated. Remove vegetable mixture from pan. Wipe pan clean with a paper towel.
4. Heat tortillas according to package directions. Divide sour cream mixture evenly among tortillas; spread to a thin layer, leaving a 1/2-inch border. Top each tortilla with 1/4 cup cheese, about 1/4 cup rice mixture, and about 1/2 cup vegetable mixture. Roll up each, jelly-roll fashion. Return skillet to medium heat. Add 2 burritos to pan, seam side down; cook 1 minute on each side or until browned. Repeat procedure with remaining burritos. Garnish with cilantro leaves, if desired.