Preheat the grill to medium high heat. Clean grates.
Cut the potatoes into halves and place in a pot of salted water. Bring to a boil and cook about 8 minutes, until tender. Drain and set aside.
Meanwhile, heat a large skillet over medium high heat and cook the peppers, onions, and garlic with a tablespoon of water for 5 minutes, until softened.
Stir in the tomato paste and cook for another minute.
Add another tablespoon of water to thin out the tomato paste and cook until veggies are tender but still have a crispness.