Make the dressing: In a small bowl, whisk together lime zest, lime juice, rice vinegar, honey, Dijon, oil, salt, and a few grinds of pepper until smooth and slightly thickened.
Prep the mango: Peel the mangoes. Slice the cheeks off the pit, then cut into thin matchsticks or small cubes. Aim for firm-ripe fruit so it holds its shape.
Prep the veggies: In a large bowl, combine shredded cabbage, carrot, bell pepper, green onions, cilantro, and jalapeño if using.
Toss it together: Add the mango to the bowl.
Pour in about two-thirds of the dressing and toss gently until everything is coated.
Taste and tweak: Add more dressing, salt, or lime to hit the sweet-tangy balance you like. If using nuts, fold them in just before serving.
Rest briefly: Let the slaw sit for 10–15 minutes so the flavors meld and the cabbage softens slightly.
Serve: Pile it next to grilled protein, stuff it into tacos, or enjoy it straight from the bowl.