To make the orange dressing: Heat the grapeseed oil in a skillet over medium heat. Add red onion and garlic and allow to sweat for about 10 minutes. Reduce heat to low and stir in tomatoes, orange and chives and cook for an additional 2 minutes over low heat. Remove from heat and stir in fresh mint leaves. Set aside until needed.
For the crab salad: Combine hoisin sauce, soy sauce and mayonnaise in a medium mixing bowl. Gently fold in crabmeat. Using a 2 or 3-inch circle cutter, form crabmeat into rounds. Top with orange dressing and 2 tablespoons pea tendrils. Serve chilled.