You could try:
2 x 400g cans chickpeas (drained)
1 small onion
2 carrots (roughly chopped)
1 large garlic clove
1 tsp coriander
1 tsp cumin
small handful parsley
Preheat grill to medium. Tip all ingredients into bowl, whizz with a blender briefly but keep some of chunky texture of chickpeas. Shape into 6 burgers. Brush both sides lightly with oil. Place in grill pan lined with foil and grill for 4-5 mins on each side.