PREHEAT broiler. Mix shredded cheese, cottage cheese, mayonnaise, crabmeat, half of the green onions, the pimientos and horseradish.
SPREAD each cracker with 2 tsp. of the cheese mixture. Sprinkle evenly with the remaining green onions; place in single layer on baking sheet.
BROIL, 4 inches from heat, 1 to 2 min. or until crab topping is heated through and cheese is melted. Serve warm.