Heat oil over medium high heat in a large skillet or wok. Stir in onions and cook for 1 minute. Add garlic and ginger and cook for 30 seconds. Stir in tofu and cook until golden brown on all sides, about 4 minutes. In a small sauce pan combine water, rice wine vinegar, honey and soy sauce and bring to a simmer. Cook for 2 minutes and stir in cornstarch mixture. Simmer until sauce thickens. Add carrots and bell pepper to the skillet and cook for another 2 minutes. Add bok choy to skillet and toss to coat. Pour thickened sauce over vegetables and tofu. Garnish with scallions and serve immediately with rice.