Preheat oven to 500°. Cut kabocha squash into 1-inch cubes; place in bowl. Add 1 tablespoon olive oil, 1/4 teaspoon salt, and 1/8 teaspoon pepper, tossing well. Place squash on a baking sheet; roast until edges are lightly browned and soft (15 minutes). Preheat broiler. Cover each baguette slice with 1/4 of goat cheese. Broil until browned and soft (2 minutes). Place squash, frisée lettuce, chopped chives, currants, red wine vinegar, 1 tablespoon olive oil, 1/4 teaspoon salt, and 1/8 teaspoon pepper in bowl; toss. Divide among 4 plates; top with toast. Garnish each with 1 teaspoon toasted pumpkin seeds; serve.