Toast the 4 slices of whole wheat bread until golden and crisp. Cut each slice into two rectangles to make 8 slider bases.
Cut the avocados in half, remove the pits, and scoop the flesh into a mixing bowl. Add the lime juice, salt, and black pepper, then mash until smooth but still chunky.
Spread the mashed avocado evenly over the 8 toast rectangles.
Place two olive slices on each slider to form eyes. Add one halved cherry tomato below the eyes to create a mouth.
Lay one chive across the top of each slider to resemble hair. Serve right away.