Heat grill to high; lightly oil grates. Place peppers on grill skin side down; cover. Cook, moving peppers on grill as they char (keep skin side down), until skin is charred all over and peppers are crisp-tender, about 15 minutes.
Immediately transfer peppers to a medium bowl and cover bowl with a towel or a plate; let stand 5 minutes.
Meanwhile, use 1 tablespoon of oil (divide evenly) to brush one side of each slice of bread. Place oil side down on grill and cook until toasted, about 1 minute.
Remove peppers from bowl and, using a paring knife, scrape off charred skin. Cut lengthwise into 1/2 inch strips. In a medium bowl toss pepper strips with remaining tablespoon oil, vinegar, feta, and basil; season with salt and pepper. Spoon mixture evenly onto the grilled side of each slice of bread.
Per serving: 224 calories; 8 g protein; 11 g fat; 27 g carb; 4 g fiber