Grilled Pizza on Portobello Crust

2 roasted red, yellow or green bell peppers (or a combination
    of them; you can use roasted peppers purchased from the deli
    case or bottled roasted peppers if you wish)
1 tablespoon vegetable or olive oil
1 small red onion, halved, thinly sliced
1 garlic clove, finely chopped
1/4 teaspoon dried oregano, preferably Mexican
Salt to taste
6 medium portobello mushroom caps, about 4 inches in diameter
3/4 cup any flavor Grilling Sauce
1 cup shredded cheese, such as Monterey jack or mozzarella
2 to 3 tablespoons chopped fresh cilantro

Cut the roasted peppers into 1/4-inch wide strips; cut the strips in half.

Heat the oil in a small skillet until hot. Add the onion slices and saut