Rinse olives under cool water for 1 minute in a colander.

Cover olives with cool water in a large bowl.

Soak olives for 4 hours to remove excess salt and drain well.

Make harissa: Grind cuminseed, coriander seeds, and caraway seeds fine using a mortar with a pestle, an electric spice grinder, or a cleaned coffee grinder.

If using mortar and pestle, add chilies, garlic, and salt and pound to taste.

If using a spice or coffee grinder, transfer ground seeds to a small food processor and add chilies, garlic, and salt.

Grind the mixture to a paste.

Add roasted red bell pepper and olive oil and pulse or puree to a coarse paste.

In a large bowl, stir together harissa and olives and marinate, covered and chilled, for at least 6 hours or overnight.

Olives may be prepared 1 week ahead and kept chilled, covered.

Serve olives at room temperature.

To roast peppers: Char peppers over an open flame or on a rack set over an electric burner, turning, until skins are blackened, 4 to 6 minutes.

Alternatively, broil peppers on the rack of a broiler pan under a preheated broiler about 2 inches from heat, turning every 5 minutes, for 15 to 20 minutes, until skins are blistered and charred.

Transfer peppers to a bowl and let stand, covered, until cold enough to handle.

Keeping peppers whole, peel them, starting at the blossom end.

Cut off pepper tops and discard seeds and ribs.