Preheat griddle side of grill pan or large cast-iron skillet over medium-high heat.
Char red pepper, blackening all of the skin, over flame on stove top or under broiler with oven door cracked to allow steam to escape. Place pepper in a bowl, cover tightly with plastic wrap and cool to handle. Seed pepper and slice.
Heat EVOO in a large skillet, a turn of the pan, over medium-high heat. Add bacon and crisp it up then add fresh chilies and garlic. Stir, add onions and cubanelle peppers, and cook to tender-crisp, 5 minutes, stirring frequently. Add sliced red bell peppers and reduce heat to low.