Stir together crabmeat, mascarpone, cream cheese, garlic, scallions, chili sauce, and salt in a large bowl until combined. Stir together white and black sesame seeds; spread in an even layer on a large plate. Gently shape crab mixture into a ball, and carefully roll in sesame seeds until covered. Place on a serving plate; chill, uncovered, until set, about 30 minutes. Serve with wonton chips.