1. Combine first 5 ingredients and 1 tablespoon lime juice in a medium bowl; toss to coat. Sprinkle with 1/4 teaspoon salt.
2. Preheat oven to 450°.
3. Place zucchini and poblano on a jelly-roll pan; drizzle with oil. Sprinkle with cumin and 1/4 teaspoon salt; toss to coat. Bake at 450° for 20 minutes or until tender and lightly browned.
4. Combine garlic, beans, and remaining 1/4 teaspoon salt in a small saucepan over medium heat; bring to a simmer. Cook 10 minutes or until slightly thickened. Coarsely mash with a potato masher.
5. Lightly coat both sides of tortillas with cooking spray. Arrange tortillas in a single layer on a baking sheet. Bake at 450° for 6 minutes. Turn tortillas over; bake an additional 3 minutes or until crispy.
6. Combine sour cream, milk, and remaining 1 teaspoon lime juice in a small bowl, stirring with a whisk until smooth.
7. Place 2 tortillas on each of 4 plates. Layer each tortilla with about 2 tablespoons bean mixture, 1/4 cup zucchini mixture, 1 teaspoon sour cream mixture, 1/2 teaspoon picante sauce, and about 2 tablespoons radish mixture. Serve immediately.