Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper and position an oven rack in the center.

In a large bowl, beat the 3 eggs. Add the cauliflower florets and toss until evenly coated.

Place the 1 1/4 cups Panko in a separate shallow bowl. Working in batches, dredge each egg-coated floret in the Panko, pressing gently so crumbs adhere. Arrange the coated florets in a single layer on the prepared baking sheet, leaving space between pieces.

Bake the cauliflower at 425°F for 15 minutes. About halfway through (7–8 minutes), turn the florets for more even browning. After 15 minutes, switch the oven to broil and broil the cauliflower 2–3 minutes more, watching closely, until the coating is crisp and golden.

While the cauliflower bakes, reserve 2 tablespoons of the 1 cup orange juice and whisk those 2 tablespoons with the 2 teaspoons cornstarch until smooth to make a slurry.

Heat a large skillet over medium heat. Add the 1 tablespoon sesame oil, then the 4 grated garlic cloves, 1 tablespoon grated fresh ginger, and 1/2–1 teaspoon chili flakes. Cook, stirring, 1–2 minutes until fragrant (do not let the garlic burn).

Add the remaining orange juice (the rest of the 1 cup), 1/3 cup tamari/soy sauce, 2 tablespoons rice vinegar, and 2 tablespoons honey to the skillet. Bring the mixture to a boil, then reduce to a simmer and whisk in the cornstarch slurry. Cook, stirring, until the sauce thickens and becomes glossy, about 1 minute. Remove from heat and stir in the 1 tablespoon orange zest.

Transfer the baked cauliflower to a large bowl (or return it to the skillet off the heat). Pour the sauce over the cauliflower and toss gently until all pieces are evenly coated.

Serve the sauced cauliflower topped with the 2 tablespoons toasted sesame seeds and sliced green onions.