Over medium heat, warm olive oil in a medium-sized saucepan. Add quinoa and stir constantly until quinoa is lightly brown (about 4 minutes). Increase heat to medium high, stir in orange juice, water, and salt and bring to a boil. Reduce heat to medium, cover and cook until the liquid is absorbed (about 15 minutes).
Fluff quinoa with a fork and spread over a baking sheet to cool.
Place whole red bell peppers on a baking sheet under the broiler on high, turning occasionally until bell peppers' skin blisters and turns black. Remove from oven and immediately cover with foil tightly. Set aside for 30 minutes or until peppers are cool enough to handle. Remove stems and slice into quarters. Remove peels and seeds and discard.
If adding pine nuts, toast pine nuts in a medium skillet over medium heat stirring occasionally until golden brown (about 5 minutes). Transfer to a plate to cool
In a large mixing bowl, whisk together 1/4 cup olive oil and vinegar. Transfer quinoa, peppers, pine nuts, cucumber, tomato, basil, mint and tofu and toss until thoroughly combined. Salt and pepper to taste.
Serve over a bed of spinach.