Full Sun? All of these are heat-loving and very drought tolerant:
African daisies/gazania (flowers are white, cream, yellow, gold, orange, red, copper, purple. All with dark eyes)
Dianthus (pink, white, purples. Blossoms can single, double, or ruffled)
Ice plant (delsosperma)--which despite it's name is actually a heat-loving succulent perennial. Ice plants are tough buggers--you can even plant directly into gravel and they'll grow. Very easy to propagate by cuttings. Bright hot pink flowers.