Peel and roughly grate the carrots. Halve the avocado, remove the stone and remove the pulp. Chop with a fork. Mix the avocado in a bowl with the shredded carrots, lemon juice, salt and pepper.
Cut the cucumber into thin slices.
Brush the bread slices with the cottage cheese or cream cheese and top with slices of cucumber. Spread the avocado and carrot mixture on top.