Roasted red peppers in salad - do you have to roast fresh or can you use ones from a jar (like Pastene brand)?

Roasting peppers on a gas range is pretty easy. Blacken them on all sides, drop them in a paper bag and let steam. Rub off the skin and then stem and seed them. Don't worry if there is still a bit of blackened skin left on. Alternatively you could put them in a bowl (instead of a bag), cover with cling wrap.
As to jarred peppers I really like piquillo peppers imported from Spain. Excellent flavor and available on-line from Zingermans, La Tienda and Spanish Table. I like the Ortiz brand.