- Preheat oven to 400ºF and line a baking sheet with parchment paper. Toss cubed sweet potatoes in 1 tablespoon olive oil and spread on baking sheet. Roast for 15 minutes.
- Blot excess moisture from chickpeas and spread on baking sheet with sweet potatoes. Add garlic cloves to sheet pan. Return to oven for 15 minutes longer, then cool for 10 minutes at room temperature.
- Heat 1 tablespoon of olive oil over medium heat in a grill pan. Add pineapple slices and grill for 3-4 minutes on each side. Set aside.
- Combine cooked brown rice, oat flour, sweet potatoes, chickpeas, garlic, 2 tablespoons of teriyaki glaze, cilantro, ginger and salt in a food processor. Pulse until mostly smooth.
- Form mixture into 4 patties. Heat remaining 1 tablespoon of olive oil over medium heat in a nonstick pan for 1 minute. Add 4 patties and cook for 3-4 minutes on each side. Brush veggie burgers with remaining teriyaki glaze.
- Top burger bun bottoms with arugula. Place a burger on each bun and top with grilled pineapple. Brush with additional teriyaki glaze if desired. Add bun tops and serve right away.