Preheat your broiler, grill, or a gas burner to high. Place the 6 whole bell peppers directly on the grill, over the burner, or on a foil-lined baking sheet under the broiler. Roast, turning occasionally, until the skins are evenly blackened and blistered on all sides (about 10–15 minutes total).
Transfer the hot peppers to a heatproof bowl and cover tightly with plastic wrap or a lid. Let them steam for 10–15 minutes to loosen the skins.
When cool enough to handle, peel off and discard the charred skins. Cut off the stems, slice the peppers open, and remove and discard the seeds and membranes.
Slice the peeled pepper flesh into long, thin strips and place the strips in a medium salad bowl.
Add the 2 cloves minced garlic, 1 tablespoon extra virgin olive oil, and 1/2 teaspoon salt (or more to taste) to the peppers. Gently toss until the peppers are evenly coated.
Cover the bowl and refrigerate for at least 2 hours to marinate. Serve chilled or at room temperature.