How to Make It
Light a grill. In a food processor, mince the basil and garlic, then add the oil and process to a paste. Transfer to a bowl and fold in the grated cheese. Season the pesto with salt and pepper.
Brush the bell peppers, squash, zucchini and sweet onion with oil; season with salt and pepper. Grill the vegetables over moderately high heat, turning once, until charred and just tender. Discard the charred skin from the peppers. Cut the grilled vegetables into 1-inch squares and transfer to a large bowl. Add the tomatoes and red onion.
In a small bowl, whisk the 3/4 cup of oil with the lemon juice, parsley, vinegar, garlic and thyme. Season with salt and pepper, pour it over the vegetables and toss.
Brush the bread on both sides with oil. Grill over moderately high heat, turning once, until toasted, 2 minutes. Spread each toast with a rounded tablespoon of the pesto, then top with the grilled vegetables and the ricotta salata and serve.