Preheat a grill or grill pan over medium-high. In a medium saucepan, heat 1 1/2 tsp. oil over medium. Add the rice and stir until well coated with oil, about 1 minute. Add the lemon juice, 2 1/3 cups water and 1 tsp. salt; bring to a boil. Reduce the heat to low; cover and simmer until the rice is tender, about 45 minutes. Fluff with a fork.
Meanwhile, toss the salmon with the remaining 1 1/2 tsp. oil. In a small bowl, mix 1 tsp. pepper with the cinnamon; sprinkle all over the salmon. Thread tomatoes, zucchini and salmon on eight metal or wooden skewers (soak wooden ones in water for 30 minutes). Grill, turning occasionally, until the salmon is cooked and zucchini is crisp-tender, about 10 minutes. Season with salt.
Stir the mint into the rice; transfer to a platter. Top with the skewers; serve with the lemon wedges.