In a large saucepan, heat the olive oil over medium heat. Add the onion and cook until soft. Add the summer squash and zucchini, and continue cooking until tender, about 5 minutes. Stir in the garlic, tomatoes, jalapeno, corn and beans. Cook until the vegetables are tender-crisp, about 5 minutes. Add the cilantro and remove from the heat.
Heat a large frying pan (without a nonstick surface) over medium heat. Add 1 tortilla to the hot pan and heat until softened — about 20 seconds a side. Repeat with the remaining tortillas.
To serve, divide the tortillas among individual plates. Scoop an equal amount of the vegetable mixture onto each tortilla. Top each with 2 tablespoons of the salsa. Serve immediately.