My husband hates mushrooms, and since that is the "meat" of this vegetarian dish, I threw a chicken breast on the grill for him. You are welcome to try it with chicken or keep it vegetarian!
3 tablespoons olive oil
2 to 3 medium zucchini, cut into 1/2-inch-wide slices on the diagonal
2 portobello mushrooms, stemmed
1 chicken breast (optional)
1 bunch scallions, root ends trimmed
4 flour tortillas
1 cup shredded pepper jack cheese
2 tomatoes, chopped
3 cups fresh tomato salsa
1 lime, cut into 4 wedges, for serving
Heat the grill to high; lightly oil the grates. In separate piles, arrange the zucchini, mushrooms, and scallions on a backing sheet. Drizzle with 2 tablespoons of the oil; season with salt and pepper. (If grilling chicken, season with salt and pepper and add to grill first.) Grill vegetables, turning once, until lightly browned and tender, 2 minutes for scallions, 6 minutes for mushrooms, and 8 minutes for zucchini. Return all vegetables to the baking sheet. (Slice chicken into 1/2-inch strips.) Slice mushrooms into 1/2-inch wide strips. Slice scallions into 2-inch pieces. Set aside.
Brush the tortillas with remaining tablespoon oil; grill, turning frequently, until browned and very crispy, about 2 minutes. Immediately top warm tortillas with shredded cheese.
To serve, cover tortilla with mushrooms and zucchini. Top with tomatoes, salsa, and scallions; serve with lime wedges.