Preheat the oven to 450°F. Line a medium baking pan or baking sheet with parchment paper.
In a medium bowl, combine the tomatoes with the 1 tablespoon oil and toss. Season with salt and pepper. Place the tomatoes cut side up on the sheet (or spread out the whole grape tomatoes). Roast until the tomatoes have browned, 40 to 50 minutes. Set aside.
Meanwhile, char the peppers over an open burner flame, turning as the skin blisters, 12 to 15 minutes. Alternately, preheat the broiler and place the peppers on a large baking sheet and broil close to the heat source, turning every 10 minutes or so, until the peppers are charred on all sides and very soft, 30 to 35 minutes. Place the roasted peppers in a paper bag and close the bag. The steam created inside the bag will help loosen the skins, making peeling the peppers easier. Let them cool long enough so you can handle them, then peel them. Halve the peppers and discard their peel, seeds, and stems. Cut each half lengthwise into thirds and set aside.
Meanwhile, toast the cumin seeds in a small pan over low heat, stirring occasionally, until lightly colored and fragrant, 3 to 5 minutes. Transfer the seeds to a small bowl and set aside. Add the ¼ cup oil to the pan and sauté the garlic over low heat, stirring occasionally, until the garlic begins to color. Remove from the heat and set aside.
Using a mortar and pestle, partially crush the cumin seeds. You can also grind them coarsely in a spice grinder.
Pile the parsley leaves on a platter. In a large bowl, combine the tomatoes, peppers, garlic with its oil, crushed cumin and lemon juice and toss. Season with salt, transfer onto the parsley leaves and serve.