Slice each cucumber into thick rounds about 1.5 cm thick. You need 16 rounds total.
Halve all the black olives crosswise to make 32 flat circles.
Cut the red capsicum in half, remove the seeds, and cut it into thin curved strips about 3 cm long.
Lay the cucumber rounds on a tray in a single layer.
Press two olive halves, cut-side down, onto the upper portion of each cucumber round for the eyes.
Place one curved strip of red capsicum on the lower portion of each cucumber round to form the wide frog smile.
Serve immediately or refrigerate loosely covered for up to 3 hours.