Heat 1 tablespoon of the oil in a large nonstick skillet or a wok over high. Add snap peas, onion, and bell pepper, and cook, stirring often, until vegetables are starting to soften, about 2 minutes. Add garlic, and cook, stirring constantly, 1 more minute. Remove vegetable mixture from skillet to a plate. Add remaining 1 tablespoon oil and all of beef mixture to skillet; cook stirring often, until meat browns, about 2 minutes. Return vegetables to skillet; add water. Stir-fry until sauce is thick and coats mixture well, about 1 more minute. Serve over cooked brown rice, and top with scallions. Add cilantro and crushed red pepper, if desired.