Any chain restaurant applying for an operating license in Florida ought to have to complete a course in the Char-Hut methodology. This little Florida franchise, which opened its first outlet in 1976 to sell char-grilled burgers, onion rings, and hot dogs, is doing so many things right that it's easy to lose track. It serves nutritious food at low prices - a fresh-ground, lean burger that's won approval from the American Heart Association; side orders of whole baked sweet or Idaho potatoes, black beans and rice, cole slaw, and plantains; salads topped with grilled tuna steak or chicken. Further, it locates its franchises in western communities and reaches out to its neighbors with specials - discounts for local teachers and faculty, free food for youngsters wearing uniforms on game days, Jr. burgers and hot dogs for every A a kid earns on her report card. It has stuff for vegetarians. Discounts for seniors. It's so squeaky-clean, it's almost painful; the food is delicious. With every patty flipped over a hot grill, Char Hut sews up one small tear in fast food's tattered reputation.