For the veggie mini burgers: Bring 1 cup water to a boil in a small saucepan. Add the quinoa, cover and reduce the heat to low. Cook until the water is absorbed, 15 to 20 minutes. Remove the quinoa from the saucepan and spread out onto a baking sheet. Cool completely.
Puree half the can of cannellini in the bowl of a food processor. Add 1/4 cup of the cooked quinoa (save the rest for another time), the cannellini puree, the remaining whole cannellini, corn, panko, cilantro, salt, chili powder, cumin, garlic, pepper and lemon juice in a large bowl. Mix until the mixture comes together. Form 8 small patties, about 2-ounces each. Refrigerate the patties for 15 minutes to firm up.
Heat the oil in a large nonstick skillet over medium heat. Cook the patties until golden brown, 5 to 8 minutes per side.
For the sandwich build: Place 2 patties inside each pita, top with a dollop of Cucumber Yogurt Sauce, some lettuce and tomato. Serve while on the elliptical machine.
Mix the cucumbers, yogurt, lemon juice, tahini, sugar, garlic in a small bowl. Sprinkle with hot sauce, salt and pepper.