Heat grill to high; lightly oil grates. Mince 1 garlic clove, and place in a shallow dish. Add lemon juice and 1 tablespoon oil; season with salt and pepper. Add chicken, and toss to coat. Let stand at room temperature at least 5 minutes (and up to 30).
Brush bread on both sides with remaining 2 tablespoons oil; season with salt and pepper. Grill bread until beginning to char, about 1 minute per side. Cut remaining garlic clove in half, and rub cut sides over grilled bread; set bread aside (discard garlic clove).
Grill chicken until opaque throughout, 1 to 3 minutes per side. Serve with garlic bread and lemon wedges.