Even if you don't can your own tomato sauce, you can make this fresh and satisfying bruschetta.
Preheat oven to 400 degrees. Brush 1/4 cup olive oil over bread, and spread on a baking sheet. Bake until golden brown, 10 to 15 minutes. Transfer to a wire rack to cool slightly.
In a large saute pan, heat remaining 2 tablespoons oil over medium heat. Add onion and garlic, and season with salt and pepper. Cook, stirring, until onions begin to brown, about 5 minutes. Add tomatoes, parsley, and thyme; increase heat to medium-high. Cook, stirring, until tomatoes start to dry and mixture is caramelized, about 10 minutes.
Spread a heaping teaspoon of ricotta over each toast slice; top with a teaspoon of tomato mixture. Garnish with thyme, and serve.